diff --git a/addons/base_setup/views/res_config_settings_views.xml b/addons/base_setup/views/res_config_settings_views.xml
index ef7bcbbf595..6e9adb076b9 100644
--- a/addons/base_setup/views/res_config_settings_views.xml
+++ b/addons/base_setup/views/res_config_settings_views.xml
@@ -51,7 +51,7 @@
                                             </span>
                                         </div>
                                         <div class="mt8">
-                                            <button name="%(base.action_view_base_language_install)d" icon="fa-arrow-right" type="action" string="Add Language" class="btn-link"/>
+                                            <button name="%(base.action_view_base_language_install)d" icon="fa-arrow-right" type="action" string="Add Languages" class="btn-link"/>
                                         </div>
                                         <div class="mt8" groups="base.group_no_one">
                                             <button name="%(base.res_lang_act_window)d" icon="fa-arrow-right" type="action" string="Manage Languages" class="btn-link"/>
diff --git a/addons/crm/views/crm_lead_views.xml b/addons/crm/views/crm_lead_views.xml
index 1ea504dce85..1a0b47d7913 100644
--- a/addons/crm/views/crm_lead_views.xml
+++ b/addons/crm/views/crm_lead_views.xml
@@ -129,11 +129,11 @@
                                 <field name="lang_code" invisible="1"/>
                                 <label for="lang_id" attrs="{'invisible': [('lang_active_count', '&lt;=', 1)]}"/>
                                 <div class="o_row" attrs="{'invisible': [('lang_active_count', '&lt;=', 1)]}">
-                                    <field name="lang_id" options="{'no_quick_create':True,'no_create_edit':True,'no_open': True,}"/>
+                                    <field name="lang_id" options="{'no_quick_create': True, 'no_create_edit': True, 'no_open': True}"/>
                                     <button
                                         type="action"
                                         name="%(base.res_lang_act_window)d"
-                                        class="btn-sm btn-link mb4 fa fa-globe"
+                                        class="oe_edit_only btn-sm btn-link mb4 fa fa-globe"
                                         aria-label="More languages"
                                         groups="base.group_system"
                                         title="More languages"
@@ -309,11 +309,11 @@
                                         <field name="lang_active_count" invisible="1"/>
                                         <label for="lang_id" attrs="{'invisible': [('lang_active_count', '&lt;=', 1)]}"/>
                                         <div class="o_row" attrs="{'invisible': [('lang_active_count', '&lt;=', 1)]}">
-                                            <field name="lang_id" options="{'no_quick_create':True,'no_create_edit':True,'no_open': True,}"/>
+                                            <field name="lang_id" options="{'no_quick_create': True, 'no_create_edit': True, 'no_open': True}"/>
                                             <button
                                                 type="action"
                                                 name="%(base.res_lang_act_window)d"
-                                                class="btn-sm btn-link mb4 fa fa-globe"
+                                                class="btn-sm btn-link mb4 oe_edit_only fa fa-globe"
                                                 aria-label="More languages"
                                                 groups="base.group_system"
                                                 title="More languages"
diff --git a/addons/l10n_multilang/models/l10n_multilang.py b/addons/l10n_multilang/models/l10n_multilang.py
index 07b8e7f9633..e52f1436035 100644
--- a/addons/l10n_multilang/models/l10n_multilang.py
+++ b/addons/l10n_multilang/models/l10n_multilang.py
@@ -4,7 +4,7 @@
 from collections import defaultdict
 import logging
 
-from odoo import api, models
+from odoo import models
 
 _logger = logging.getLogger(__name__)
 
@@ -151,26 +151,30 @@ class BaseLanguageInstall(models.TransientModel):
 
     def lang_install(self):
         self.ensure_one()
-        already_installed = self.lang in [code for code, _ in self.env['res.lang'].get_installed()]
         res = super(BaseLanguageInstall, self).lang_install()
-        if already_installed:
+        lang_codes = set(self.lang_ids.mapped('code'))
+        installed = {code for code, __ in self.env['res.lang'].get_installed()}
+        to_install = lang_codes - installed
+        if not to_install:
             # update of translations instead of new installation
             # skip to avoid duplicating the translations
             return res
 
         # CoA in multilang mode
         for coa in self.env['account.chart.template'].search([('spoken_languages', '!=', False)]):
-            if self.lang in coa.spoken_languages.split(';'):
+            coa_langs_codes = to_install & set(coa.spoken_languages.split(';'))
+            if coa_langs_codes:
                 # companies on which it is installed
                 for company in self.env['res.company'].search([('chart_template_id', '=', coa.id)]):
                     # write account.account translations in the real COA
-                    coa._process_accounts_translations(company.id, [self.lang], 'name')
+                    coa._process_accounts_translations(company.id, coa_langs_codes, 'name')
                     # write account.group translations
-                    coa._process_account_group_translations(company.id, [self.lang], 'name')
+                    coa._process_account_group_translations(company.id, coa_langs_codes, 'name')
                     # copy account.tax name translations
-                    coa._process_taxes_translations(company.id, [self.lang], 'name')
+                    coa._process_taxes_translations(company.id, coa_langs_codes, 'name')
                     # copy account.tax description translations
-                    coa._process_taxes_translations(company.id, [self.lang], 'description')
+                    coa._process_taxes_translations(company.id, coa_langs_codes, 'description')
                     # copy account.fiscal.position translations
-                    coa._process_fiscal_pos_translations(company.id, [self.lang], 'name')
+                    coa._process_fiscal_pos_translations(company.id, coa_langs_codes, 'name')
+
         return res
diff --git a/addons/website/models/res_lang.py b/addons/website/models/res_lang.py
index 1f1f5ac7028..7e0685000f5 100644
--- a/addons/website/models/res_lang.py
+++ b/addons/website/models/res_lang.py
@@ -1,7 +1,6 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo import api, models, tools, _
-from odoo.addons.website.models import ir_http
 from odoo.exceptions import UserError
 from odoo.http import request
 
@@ -21,3 +20,17 @@ class Lang(models.Model):
         if request and getattr(request, 'is_frontend', True):
             return self.env['website'].get_current_website().language_ids.get_sorted()
         return super().get_available()
+
+    def action_activate_langs(self):
+        """
+        Open wizard to install language(s), so user can select the website(s)
+        to translate in that language.
+        """
+        return {
+            'type': 'ir.actions.act_window',
+            'name': _('Add languages'),
+            'view_mode': 'form',
+            'res_model': 'base.language.install',
+            'views': [[False, 'form']],
+            'target': 'new',
+        }
diff --git a/addons/website/static/tests/tours/automatic_editor.js b/addons/website/static/tests/tours/automatic_editor.js
index 5e8dc5b2efe..7c7c7d125d6 100644
--- a/addons/website/static/tests/tours/automatic_editor.js
+++ b/addons/website/static/tests/tours/automatic_editor.js
@@ -17,15 +17,28 @@ tour.register('automatic_editor_on_new_website', {
         trigger: 'a.o_add_language',
     },
     {
-        content: "Select dropdown",
-        trigger: 'select[name=lang]',
-        run: () => {
-            $('select[name="lang"]').val('"pa_GB"').change();
-        }
+        content: "type Parseltongue",
+        trigger: 'div[name="lang_ids"] .o_input_dropdown input',
+        run: 'text Parseltongue',
+    },
+    {
+        content: 'select Parseltongue',
+        trigger: 'div[name="lang_ids"] .o_input_dropdown input',
+        extra_trigger: '.dropdown-item:contains(Parseltongue)',
+        run: function () {
+            // The dropdown element is outside the action manager, and can therefor not
+            // be selected directly by "trigger".
+            // That's why we need to simulate the click in JS
+            const element = $('.dropdown-item:contains(Parseltongue)');
+            if (!element.length) {
+                console.error('Lang not found');
+            }
+            element.click();
+        },
     },
     {
         content: "load parseltongue",
-        extra_trigger: '.modal select[name="lang"]:propValueContains(pa_GB)',
+        extra_trigger: '.modal div[name="lang_ids"] .badge-pill .o_tag_badge_text:contains(Parseltongue)',
         trigger: '.modal-footer button:first',
     },
     {
diff --git a/addons/website/static/tests/tours/rte.js b/addons/website/static/tests/tours/rte.js
index 233f3787395..3ab84c54bc9 100644
--- a/addons/website/static/tests/tours/rte.js
+++ b/addons/website/static/tests/tours/rte.js
@@ -21,13 +21,27 @@ tour.register('rte_translator', {
     content: "click on Add a language",
     trigger: 'a.o_add_language',
 }, {
-    content: "select Parseltongue",
-    trigger: 'select[name="lang"]',
-    run: 'text "pa_GB"',
+    content: "type Parseltongue",
+    trigger: 'div[name="lang_ids"] .o_input_dropdown input',
+    run: 'text Parseltongue',
+}, {
+    content: 'select Parseltongue',
+    trigger: 'div[name="lang_ids"] .o_input_dropdown input',
+    extra_trigger: '.dropdown-item:contains(Parseltongue)',
+    run: function () {
+        // The dropdown element is outside the action manager, and can therefor not
+        // be selected directly by "trigger".
+        // That's why we need to simulate the click in JS
+        const element = $('.dropdown-item:contains(Parseltongue)');
+        if (!element.length) {
+            console.error('Lang not found');
+        }
+        element.click();
+    },
 }, {
     content: "load Parseltongue",
     trigger: '.modal-footer button:first',
-    extra_trigger: '.modal select[name="lang"]:propValueContains(pa_GB)',
+    extra_trigger: '.modal div[name="lang_ids"] .badge-pill .o_tag_badge_text:contains(Parseltongue)',
 }, {
     content: "click language dropdown (2)",
     trigger: '.js_language_selector .dropdown-toggle',
diff --git a/addons/website/tests/test_configurator.py b/addons/website/tests/test_configurator.py
index 63c3d07e552..52364d73c34 100644
--- a/addons/website/tests/test_configurator.py
+++ b/addons/website/tests/test_configurator.py
@@ -57,7 +57,10 @@ class TestConfiguratorTranslation(TestConfiguratorCommon):
 
     def test_01_configurator_translation(self):
         with mute_logger('odoo.addons.base.models.ir_translation'):
-            self.env["base.language.install"].create({'lang': 'fr_FR', 'overwrite': True}).lang_install()
+            self.env["base.language.install"].create({
+                'overwrite': True,
+                'lang_ids': [(6, 0, [self.env.ref('base.lang_fr').id])],
+            }).lang_install()
         feature = self.env['website.configurator.feature'].search([('name', '=', 'Privacy Policy')])
         feature.with_context(lang='fr_FR').write({'name': 'Politique de confidentialité'})
         website_fr = self.env['website'].create({
diff --git a/addons/website/views/res_config_settings_views.xml b/addons/website/views/res_config_settings_views.xml
index 02ea1a97662..1b5ba4f292a 100644
--- a/addons/website/views/res_config_settings_views.xml
+++ b/addons/website/views/res_config_settings_views.xml
@@ -45,7 +45,7 @@
                                         <field name="website_default_lang_id" options="{'no_open': True, 'no_create': True}" attrs="{'required': [('website_id', '!=', False)]}"/>
                                     </div>
                                     <div class="mt8">
-                                        <button type="action" name="%(base.action_view_base_language_install)d" string="Install a language" class="btn-link" icon="fa-arrow-right"/>
+                                        <button type="action" name="%(base.action_view_base_language_install)d" string="Install languages" class="btn-link" icon="fa-arrow-right"/>
                                     </div>
                                 </div>
                             </div>
diff --git a/addons/website/wizard/base_language_install.py b/addons/website/wizard/base_language_install.py
index b3c6225f951..63669f8c0b1 100644
--- a/addons/website/wizard/base_language_install.py
+++ b/addons/website/wizard/base_language_install.py
@@ -22,13 +22,12 @@ class BaseLanguageInstall(models.TransientModel):
 
     def lang_install(self):
         action = super(BaseLanguageInstall, self).lang_install()
-        lang = self.env['res.lang']._lang_get(self.lang)
-        if self.website_ids and lang:
-            self.website_ids.write({'language_ids': [(4, lang.id)]})
+        if self.website_ids and self.lang_ids:
+            self.website_ids.language_ids |= self.lang_ids
         params = self._context.get('params', {})
         if 'url_return' in params:
             return {
-                'url': params['url_return'].replace('[lang]', self.lang),
+                'url': params['url_return'].replace('[lang]', self.first_lang_id.code),
                 'type': 'ir.actions.act_url',
                 'target': 'self'
             }
diff --git a/addons/website/wizard/base_language_install_views.xml b/addons/website/wizard/base_language_install_views.xml
index df3062d2f77..3c52b29fd7c 100644
--- a/addons/website/wizard/base_language_install_views.xml
+++ b/addons/website/wizard/base_language_install_views.xml
@@ -6,7 +6,7 @@
         <field name="model">base.language.install</field>
         <field name="inherit_id" ref="base.view_base_language_install"/>
         <field name="arch" type="xml">
-            <group states="init" position="inside">
+            <group position="inside">
                 <field name="website_ids" widget="many2many_checkboxes" groups="website.group_multi_website"/>
             </group>
         </field>
diff --git a/odoo/addons/base/models/res_lang.py b/odoo/addons/base/models/res_lang.py
index ecca41e0bb1..95b21366869 100644
--- a/odoo/addons/base/models/res_lang.py
+++ b/odoo/addons/base/models/res_lang.py
@@ -334,6 +334,22 @@ class Lang(models.Model):
 
         return formatted
 
+    def action_activate_langs(self):
+        """ Activate the selected languages """
+        for lang in self.filtered(lambda l: not l.active):
+            lang.toggle_active()
+        message = _("The languages that you selected have been successfully installed. Users can choose their favorite language in their preferences.")
+        return {
+            'type': 'ir.actions.client',
+            'tag': 'display_notification',
+            'target': 'new',
+            'params': {
+                'message': message,
+                'type': 'success',
+                'sticky': False,
+                'next': {'type': 'ir.actions.act_window_close'},
+            }
+        }
 
 def split(l, counts):
     """
diff --git a/odoo/addons/base/views/res_lang_views.xml b/odoo/addons/base/views/res_lang_views.xml
index 79bd883ed17..0d962d81abc 100644
--- a/odoo/addons/base/views/res_lang_views.xml
+++ b/odoo/addons/base/views/res_lang_views.xml
@@ -6,6 +6,9 @@
             <field name="model">res.lang</field>
             <field name="arch" type="xml">
                 <tree string="Languages" limit="200">
+                    <header>
+                        <button name="action_activate_langs" type="object" string="Activate"/>
+                    </header>
                     <field name="name"/>
                     <field name="code" groups="base.group_no_one"/>
                     <field name="iso_code" groups="base.group_no_one"/>
diff --git a/odoo/addons/base/views/res_partner_views.xml b/odoo/addons/base/views/res_partner_views.xml
index eeb835f3ea5..b69f5776470 100644
--- a/odoo/addons/base/views/res_partner_views.xml
+++ b/odoo/addons/base/views/res_partner_views.xml
@@ -223,7 +223,7 @@
                                 <button
                                     type="action"
                                     name="%(base.res_lang_act_window)d"
-                                    class="btn-sm btn-link mb4 fa fa-globe"
+                                    class="oe_edit_only btn-sm btn-link mb4 fa fa-globe"
                                     aria-label="More languages"
                                     groups="base.group_system"
                                     title="More languages"
diff --git a/odoo/addons/base/views/res_users_views.xml b/odoo/addons/base/views/res_users_views.xml
index 5e0a305d5a1..cc84ef1ff17 100644
--- a/odoo/addons/base/views/res_users_views.xml
+++ b/odoo/addons/base/views/res_users_views.xml
@@ -245,7 +245,7 @@
                                             <button
                                                 type="action"
                                                 name="%(base.res_lang_act_window)d"
-                                                class="btn-sm btn-link mb4 fa fa-globe"
+                                                class="oe_edit_only btn-sm btn-link mb4 fa fa-globe"
                                                 aria-label="More languages"
                                                 title="More languages"/>
                                         </div>
@@ -447,7 +447,7 @@
                                         <button
                                             type="action"
                                             name="%(base.res_lang_act_window)d"
-                                            class="btn-sm btn-link mb4 fa fa-globe"
+                                            class="oe_edit_only btn-sm btn-link mb4 fa fa-globe"
                                             aria-label="More languages"
                                             groups="base.group_system"
                                             title="More languages"
diff --git a/odoo/addons/base/wizard/base_language_install.py b/odoo/addons/base/wizard/base_language_install.py
index 0d4fd9bc233..56ebe6b0a7d 100644
--- a/odoo/addons/base/wizard/base_language_install.py
+++ b/odoo/addons/base/wizard/base_language_install.py
@@ -9,45 +9,61 @@ class BaseLanguageInstall(models.TransientModel):
     _description = "Install Language"
 
     @api.model
-    def _default_language(self):
+    def _default_lang_ids(self):
         """ Display the selected language when using the 'Update Terms' action
             from the language list view
         """
         if self._context.get('active_model') == 'res.lang':
-            lang = self.env['res.lang'].browse(self._context.get('active_id'))
-            return lang.code
+            return self._context.get('active_ids') or [self._context.get('active_id')]
         return False
 
-    @api.model
-    def _get_languages(self):
-        return [[code, name] for code, _, name, *_ in self.env['res.lang'].get_available()]
-
-    lang = fields.Selection(_get_languages, string='Language', required=True,
-                            default=_default_language)
+    # add a context on the field itself, to be sure even inactive langs are displayed
+    lang_ids = fields.Many2many('res.lang', 'res_lang_install_rel',
+                                'language_wizard_id', 'lang_id', 'Languages',
+                                default=_default_lang_ids, context={'active_test': False})
     overwrite = fields.Boolean('Overwrite Existing Terms',
                                default=True,
                                help="If you check this box, your customized translations will be overwritten and replaced by the official ones.")
-    state = fields.Selection([('init', 'init'), ('done', 'done')],
-                             string='Status', readonly=True, default='init')
+    first_lang_id = fields.Many2one('res.lang',
+                                    compute='_compute_first_lang_id',
+                                    help="Used when the user only selects one language and is given the option to switch to it")
+
+    def _compute_first_lang_id(self):
+        self.first_lang_id = False
+        for lang_installer in self.filtered('lang_ids'):
+            lang_installer.first_lang_id = lang_installer.lang_ids[0]
 
     def lang_install(self):
         self.ensure_one()
         mods = self.env['ir.module.module'].search([('state', '=', 'installed')])
-        self.env['res.lang']._activate_lang(self.lang)
-        mods._update_translations(self.lang, self.overwrite)
-        self.state = 'done'
+        lang_ids = self.lang_ids
+        langs_to_activate = lang_ids.filtered(lambda l: not l.active)
+        langs_to_activate.toggle_active()
+        mods._update_translations(lang_ids.mapped('code'), self.overwrite)
         self.env.cr.execute('ANALYZE ir_translation')
 
+        if len(lang_ids) == 1:
+            return {
+                'type': 'ir.actions.act_window',
+                'res_model': 'base.language.install',
+                'res_id': self.id,
+                'view_mode': 'form',
+                'target': 'new',
+                'views': [[self.env.ref('base.language_install_view_form_lang_switch').id, 'form']],
+            }
+
         return {
-            'name': _('Language Pack'),
-            'view_mode': 'form',
-            'view_id': False,
-            'res_model': 'base.language.install',
-            'domain': [],
+            'type': 'ir.actions.client',
+            'tag': 'display_notification',
             'context': dict(self._context, active_ids=self.ids),
-            'type': 'ir.actions.act_window',
             'target': 'new',
-            'res_id': self.id,
+            'params': {
+                'message': _("The languages that you selected have been successfully installed.\
+                            Users can choose their favorite language in their preferences."),
+                'type': 'success',
+                'sticky': False,
+                'next': {'type': 'ir.actions.act_window_close'},
+            }
         }
 
     def reload(self):
@@ -57,7 +73,7 @@ class BaseLanguageInstall(models.TransientModel):
         }
 
     def switch_lang(self):
-        self.env.user.lang = self.lang
+        self.env.user.lang = self.first_lang_id.code
         return {
             'type': 'ir.actions.client',
             'tag': 'reload_context',
diff --git a/odoo/addons/base/wizard/base_language_install_views.xml b/odoo/addons/base/wizard/base_language_install_views.xml
index fb0d3429057..6fecdbb482f 100644
--- a/odoo/addons/base/wizard/base_language_install_views.xml
+++ b/odoo/addons/base/wizard/base_language_install_views.xml
@@ -2,34 +2,48 @@
 <odoo>
     <data>
 
+        <record id="base.language_install_view_form_lang_switch" model="ir.ui.view">
+            <field name="name">Switch to language</field>
+            <field name="model">base.language.install</field>
+            <field name="priority">100</field>
+            <field name="arch" type="xml">
+                <form string="Switch to language">
+                    <group>
+                        <span class="o_form_label">
+                            <strong><field name="first_lang_id" readonly="True" options="{'no_open': True}"/></strong> has been successfully installed.
+                            Users can choose their favorite language in their preferences.
+                        </span>
+                    </group>
+                    <footer>
+                        <button name="reload" string="Close" type="object" class="btn-primary" data-hotkey="q"/>
+                        <button name="switch_lang" type="object" class="btn-primary ml-1" data-hotkey="w">
+                            Switch to <field name="first_lang_id" class="text-white" style="pointer-events: none;"/> &amp; Close
+                        </button>
+                    </footer>
+                </form>
+           </field>
+        </record>
+
         <record id="view_base_language_install" model="ir.ui.view">
             <field name="name">Load a Translation</field>
             <field name="model">base.language.install</field>
             <field name="arch" type="xml">
                 <form string="Load a Translation">
-                    <field name="state" invisible="1"/>
-                    <group states="init">
-                        <field name="lang"/>
+                    <group>
+                        <field name="lang_ids" widget="many2many_tags"
+                            context="{'active_test': False}" options="{'no_quick_create': True, 'no_create_edit': True}"/>
                         <field name="overwrite" groups="base.group_no_one"/>
                     </group>
-                    <group states="done" colspan="4">
-                        <span class="o_form_label"><strong><field name="lang" readonly="True" force_save="1"/></strong> has been successfully installed.
-Users can choose his favorite language in their preferences.</span>
-                    </group>
-                    <footer states="init">
+                    <footer>
                         <button name="lang_install" string="Add" type="object" class="btn-primary"/>
                         <button special="cancel" data-hotkey="z" string="Cancel" class="btn-secondary"/>
                     </footer>
-                    <footer states="done">
-                        <button name="reload" string="Close" type="object" class="btn-primary" data-hotkey="q"/>
-                        <button name="switch_lang" type="object" class="btn-primary" data-hotkey="w">Switch to <field name="lang" readonly="True" force_save="1"/> &amp; Close</button>
-                    </footer>
                 </form>
            </field>
         </record>
 
         <record id="action_view_base_language_install" model="ir.actions.act_window">
-            <field name="name">Add Language</field>
+            <field name="name">Add Languages</field>
             <field name="type">ir.actions.act_window</field>
             <field name="res_model">base.language.install</field>
             <field name="view_mode">form</field>
diff --git a/odoo/addons/test_translation_import/tests/test_term_count.py b/odoo/addons/test_translation_import/tests/test_term_count.py
index 2081d9aff09..81b06f9eb37 100644
--- a/odoo/addons/test_translation_import/tests/test_term_count.py
+++ b/odoo/addons/test_translation_import/tests/test_term_count.py
@@ -348,7 +348,11 @@ class TestTranslationFlow(common.TransactionCase):
         """ Ensure export+import gives the same result as loading a language """
         # load language and generate missing terms to create missing empty terms
         with mute_logger('odoo.addons.base.models.ir_translation'):
-            self.env["base.language.install"].create({'lang': 'fr_FR', 'overwrite': True}).lang_install()
+            self.env["base.language.install"].create({
+                'overwrite': True,
+                'lang_ids': [(6, 0, [self.env.ref('base.lang_fr').id])],
+            }).lang_install()
+
         self.env["base.update.translations"].create({'lang': 'fr_FR'}).act_update()
 
         translations = self.env["ir.translation"].search([
diff --git a/odoo/tools/translate.py b/odoo/tools/translate.py
index c2718de1c3e..ca11767dc62 100644
--- a/odoo/tools/translate.py
+++ b/odoo/tools/translate.py
@@ -1255,5 +1255,5 @@ def load_language(cr, lang):
         l10n flavor (ex: 'fr', 'fr_BE', but not 'fr-BE')
     """
     env = odoo.api.Environment(cr, odoo.SUPERUSER_ID, {})
-    installer = env['base.language.install'].create({'lang': lang})
+    installer = env['base.language.install'].create({'lang_ids': [(6, 0, [env['res.lang'].search([('code', '=', lang)]).id])]})
     installer.lang_install()