Multilingual Templates

A campaign can only send the languages its template has, so a multilingual campaign starts in the email editor. Make the template multilingual before you set up the campaign. There is nothing to enable in the campaign itself. A multilingual template is a normal template that holds several language versions of the same email. The editor calls these versions mutations, and this documentation calls them language versions. All of them share one design. Each one can have its own text, links, images and HTML. This page shows how to operate the language controls. For what exactly is saved per language and what is shared, read How template languages work. Everything about a template’s languages is controlled from one place: the globe dropdown in the editor’s top bar, next to Preview.

On a template that has no languages yet, the dropdown is labelled Create mutation. Clicking it opens the Language settings panel, which at this point contains only an Add language button.

Editor top bar with the Create mutation dropdown open, showing the empty Language settings panel with an Add language button

As soon as the template has a language, the label changes. From then on the dropdown shows the name of the language you are currently editing, such as English or German.

Editor with the Happy Donuts template open and the globe dropdown in the top bar labelled English instead of Create mutation

Read the dropdown label before you type. It is the only indicator of which language version your edits go to.

What the Language settings panel shows

Language settings panel opened from the English dropdown: a Translate all button in the header, English outlined in green with a check mark and a Primary badge, Czech and German rows each with Set as primary, a translate icon with an arrow and a red delete button, and an Add language button at the bottom

Element	Meaning
Language row	One row per language version, with the language name and its two-letter code. Click a row to switch to that language.
Green outline and check mark	The language you are editing right now. The same name is shown on the dropdown itself.
Primary badge	The primary language: the base content and the fallback. It has no delete button.
Set as primary	Makes that language the primary one. See Change the primary language.
Translate icon and arrow	Fills that language with an AI translation. The arrow, shown once there is more than one language, picks the language to translate from. On the Primary row the button rewrites the primary content itself, so leave it alone. See Template translation.
Trash icon	Deletes that language version after a confirmation.
Translate all	Appears once the template has more than one language. Translates every secondary language from the primary.
Add language	Opens the language search to add another version.

The panel stays open while you add, switch, delete and set languages. Click anywhere outside or press Esc to close it. Starting an AI translation closes it for you.

Creating a Multilingual Template

Finish the design first

Build the template in one language and get the layout right: structures, images, buttons and styles. The layout is shared by all languages, so layout work after translating means re-checking each version.

Add the primary language

Click Create mutation, then Add language. The panel lists every available language with its native name and two-letter code.

Language settings panel with an empty Search language field above a scrollable list starting with Afar, Abkhaz, Avestan and Afrikaans, each with its code, and a Cancel button

Type in Search language to find a language by its name, native name or code, and click it.

Language settings panel with engli typed in the search field and English (English) en as the only result

The first language you add becomes the Primary language, and the content already in the template becomes that language’s content. Choose the language the template is actually written in. If your template is in German, add German first, not the language you plan to translate into.

Language settings panel showing English as the only language, outlined in green with the Primary badge, and the dropdown label changed from Create mutation to English

Add each translation

Click Add language again and pick the next language. The editor switches to the new language immediately, and the dropdown label changes to its name.

Language settings panel with English as primary, Czech selected and outlined in green, and German below it. The dropdown is labelled Czech, but the canvas still shows the English Happy Donuts content

The canvas looks the same as before. That is expected: a new language has no content of its own yet, so every block shows the primary content until you translate it. Repeat for every language you want to send. Languages already in the template are hidden from the search, so each one can be added only once.

Translate the content

Check that the dropdown shows the language you want to translate. Then click into each block and replace the content: text, button labels, links, and where needed image files and alt text. Your changes are stored for that language only, and the primary version stays untouched.You can type the translations yourself or let the editor’s AI write a first draft for one block, one language, or all languages at once. See Template translation.

Work through one language completely before moving to the next.

Find the blocks you missed

A block you have not translated does not look empty. It shows the primary text. If the Czech version has a translated heading and button but its subheading still says “Taste the most popular flavors”, that is exactly what Czech contacts would receive.

The editor does not mark untranslated blocks, so go through every secondary language block by block.

Preview every version and save

Click Preview. The language dropdown stays in the top bar, so you can flip between versions without leaving the preview. In preview it only switches languages. Adding, deleting and Set as primary are available in edit mode only.

Preview mode with the English dropdown open, listing English, Czech and German with no edit controls, English outlined in green and the English Happy Donuts email shown on the desktop view

Pick another language and the preview re-renders in that version.

Preview mode with the dropdown switched to Czech, Czech outlined in green in the open list, and the Czech version of the email shown with the heading Šťastné donuty and the button Lákavá nabídka

Check desktop and mobile. Translated text is often longer than the original, and a button label that fits in English may wrap in German. Then click Save.

Adding, translating and deleting languages all happen in your editing session. Nothing reaches the saved template, its language badge, or any campaign until you click Save. Until then, Undo reverts language changes like any other edit. The editor’s autosave history keeps snapshots of your session, languages included, but an autosave is a restore point, not a save.

Once the template is saved, its cards show a language badge such as EN · ES · FR, and any campaign that links it becomes multilingual. See Seeing a template’s languages.

Any existing template built in the visual editor can be turned into a multilingual one this way, including templates already used by past campaigns. A multilingual template also still works anywhere a single-language template does. Only campaigns pick a language per recipient. Everything else, including emails sent through the API with template_slug, always gets the primary version, and there is no language parameter to change that.

Managing Languages

Switch the language you are editing

Open the dropdown and click a language row. The canvas shows that version, and the dropdown label changes to its name. Undo and redo also restore the language that was selected at that point, so check the label again after undoing.

Change the primary language

Click Set as primary on a secondary language. The editor switches to it, and the Primary badge moves.

Language settings panel with English outlined in green as the Primary language, and the Set as primary button highlighted on the Czech row below it, next to its translate icon and red delete button

Nothing is lost. Any content the new primary was missing is filled in from the old primary, so the new primary is always complete. This also means blocks you never translated now hold text in the old primary’s language. Read through the new primary after the switch. In a draft campaign that links this template, the main Subject, sender and Reply-to fields always belong to whichever language is primary. After the switch they apply to the new primary, the old primary inherits them like any other language, and per-language values you had entered for the new primary are no longer used. Open the draft and rewrite the subjects; see Per-language subject and sender. Changing the primary also changes the campaign fallback. From then on, contacts with no matching language receive the new primary. A campaign that is already scheduled or sending is not affected, because its content is locked when it is scheduled or started.

Delete a language

Click the trash icon on a secondary language and confirm Do you really want to delete this language?. All translations for that language are removed. If it was the language you were editing, the editor switches back to the primary.

Warning dialog asking Do you really want to delete this language? with a Cancel button and a red Delete button

Two languages cannot be deleted:

The primary language. It has no trash icon. Set another language as primary first, then delete it.
The last remaining language. Once a template has a language, it always keeps at least one. A template with a single language behaves like a normal single-language template, and campaigns treat it as one.

Languages cannot be renamed or re-keyed. To replace one, add the correct language, copy the translations over, and delete the wrong one.

Translate with AI

The translate icon on a language row and the Translate all button fill language versions with an AI translation, and single blocks can be translated from the AI menu. Both overwrite translations that already exist. Template translation covers the whole workflow.

Seeing a Template’s Languages

Once a saved template has more than one language, it is marked as multilingual in three places. Template grids and list show a language badge such as EN · ES · FR on the card. Up to three languages are shown in full. With more, the badge shows the first two and +N, such as EN · ES +2. Hovering lists them all, one per line, with the primary first. The card thumbnail always shows the primary language.

The template detail page has a language picker above the preview. Switch it to read any version without opening the editor.

Template detail page for the Payment Declined template with the language picker next to Edit email open, listing English (Primary) with a check mark, Spanish and French above the English preview

The campaign template picker shows the same badge on each card in the Compose step, so you can tell a multilingual template from a single-language one before you link it.

What a Campaign Can Send

When you link a multilingual template, the campaign becomes multilingual for exactly those languages. If the template is English and German, a French contact receives the primary language. To send French, add a French version to the template. There is no per-campaign language list to maintain, and no way to send a language the template does not have. A campaign reads the template’s languages the moment the template is picked in the Compose step, with no need to save the draft first. A language added to the template while the campaign is still a draft appears in the campaign the next time it is opened. The subject line, sender and reply-to are not part of the template. Translate them per language in the campaign; see Campaign setup.

Which Templates Qualify

Templates built in the visual editor can hold languages. Campaigns link marketing templates only, so a transactional template needs the Copy to Marketing action first; see Transactional vs. Marketing Templates.
Custom HTML templates and content written directly in the campaign’s HTML editor are single-language. The multilingual mechanism needs the editor’s language versions.

Campaigns sent before multilingual campaigns existed keep working exactly as they did. Their content was stored in a single language, and Lettr does not rebuild it in other languages after the fact.

Troubleshooting

I added a language and nothing changed on the canvas

The editor did switch to the new language; the dropdown label shows its name. A new language has no content of its own, so it displays the primary content until you translate each block.

A translated email still contains primary-language text

Those blocks were never edited in that language, so they fall back to the primary content. Select the language in the editor, find the blocks, and translate them. Blocks added to the layout after translating are the usual cause.

I translated a block, but the primary language changed instead

The dropdown was showing the primary language while you typed. Undo, select the secondary language, and translate again.

I changed an image in one language and it changed everywhere

You changed a shared setting, such as the image width or padding, or you were editing the primary language, which untranslated versions follow. Select the secondary language first, then replace the image file itself.

The template's original content ended up under the wrong language

The first language you add takes over the existing content. Add the language the content is really in, click Set as primary on it, then delete the wrong one. Check the text of the new primary afterwards.

I cannot delete a language

It is the primary language, or it is the only language left. Set another language as primary first. The last remaining language cannot be removed.

I cannot add, remove or reorder items in a Products block

Items of a Products block can only be changed while the primary language is selected. Switch to the primary, change the items, then switch back and translate their texts.

A saved block asks me to select a preferred language

A saved block keeps the language versions it was saved with. When the editor shows Select preferred language, the block has several versions. Pick the one you want to work with, and your changes are stored in that version only. After inserting a saved block into a template, check it in each of the template’s languages.

A language is missing from the Add language search

It is already in the template. Each language can be added once.

The template card shows no language badge

The badge appears for saved templates with more than one language. Click Save in the editor after adding languages.

Next Steps

Template translation

Translate a block, a language, or the whole template with AI

How template languages work

What is stored per language, what is shared, and how fallback works

Contact language

Tell Lettr which contact property holds each person’s language

Campaign setup

Per-language subject and sender, the review panel, and test sends

Documentation

Quickstart

Learn

Integrations

Resources