# Languages and localisation

URL: https://aihio.ai/en/help/ai-agent/languages\
Description: A chatbot's language is three separate things: reply language, widget interface language, and knowledge search language.

The agent's language settings control **three different things**. Choose the setting according to whether you want to change the reply language, conversation interface text or source search language.

| Axis                          | Where it is set                | What it affects                                  |
| ----------------------------- | ------------------------------ | ------------------------------------------------ |
| **Reply language**            | Settings → Languages           | The language the bot writes in                   |
| **Interface language**        | Editor → Appearance → Language | The widget's own buttons and notices             |
| **Knowledge search language** | Knowledge, per source          | Which grammar rules each source is searched with |

Settings → **Languages** shows the state of all three at a glance.

## 1. Reply language

Two options:

- **Automatic.** The agent is instructed to reply in the language the customer writes in.
- **Always Finnish / Always English.** Choose a fixed reply language. This setting overrides automatic language selection, but you must still check the language and quality of generated answers.

In automatic mode, short expressions such as "ok", "kiitos" or "thanks" do not usually change the conversation language. A clear message in another language can change it. Test language switching with questions typical of your customers.

When the language cannot be determined confidently and no earlier language is available from the conversation, language resolution uses Finnish as its fallback.

### What the reply language changes

The reply language is not a finishing layer. It changes several things at once:

- **Finnish writing rules** apply only to bots replying in Finnish.
- **Form of address** (informal or formal) applies to Finnish only.
- **Suggested follow-up questions** are instructed to use the same language. Check them too if the feature is enabled.
- **Action-card instructions** are in English only when the reply language is locked to English. In Automatic mode they remain Finnish rather than switching with each visitor message.

### Finnish and English go deeper, other languages still work

In Automatic mode, the agent can also reply in other languages, such as German, French or Spanish. Answer quality depends on the model and sources; verify the language you need through testing. Semantic search can retrieve information in another language too.

Finnish and English are the fixed reply-language choices. Language-specific retrieval rules help with inflected forms. Finnish replies also receive Finnish writing instructions. These measures do not guarantee an error-free answer.

In **Settings → Languages**, use **Protected terms** to add names and abbreviations you want to keep unchanged. Select **Save a new instruction version** and test the terms in the languages you use. The list instructs the language model; it is not a rule that forcibly replaces text after generation.

## 2. Widget interface language

This is the language of the widget's **own text**: the send button, the menu, error messages. It is not the same thing as the reply language, and the two may freely differ.

The editor shows one list. Each row is a language the widget may display, and one of them is marked as the default.

> **Note — Which language choice takes effect?:**
>
> A valid host `uiLanguage` override takes priority. Otherwise, the widget uses
> the visitor's remembered language-picker choice when it is enabled and still
> allowed. On a first visit without either, browser-language detection may
> select an allowed language; otherwise, the widget opens in the default
> language.

Browser-language detection is a separate setting and is off by default. When enabled, detection can choose only a language on the list. If the browser language is not allowed, the widget uses the default language.

A previously created widget may still use the browser language when the explicit detection setting is absent and its legacy language mode is `auto`. The next save in the Editor preserves that behaviour; use the switch to turn detection off.

If you want the widget always in Finnish, set Finnish as the default and leave browser detection off. A one-language list also locks the interface to that language when detection is enabled.

### Language switcher for visitors

A separate setting adds a language choice to the widget menu. It appears only once **at least two** languages are allowed. The visitor's choice is remembered on later visits.

If you later remove a language a visitor had chosen, that visitor moves cleanly to the next allowed language.

### Your widget content

In the Content and Behaviour tabs of the editor, and in lead settings, you can choose which language version you are editing. Localised content includes:

- the chatbot name, welcome copy, and conversation starters
- launcher and tooltip text
- the answer disclaimer
- pre-chat headings and buttons, plus consent copy with its link
- the privacy notice, visible link text, and URL.

The default language is the fallback for content in other languages. For example, if English is not the default and its welcome copy is empty, the widget uses the default-language version. An empty value saved in the default language does not restore legacy single-language copy; widget-owned defaults still apply to fields that define one. The pre-chat consent copy and the privacy notice each switch together with their own link text and URL so that one notice never mixes two languages.

### Swedish

The Swedish interface translation is a draft pending native review and is not a production-support commitment. In all cases, it does not change the reply language or knowledge search.

## 3. Knowledge search language

Each source's language is detected **individually** from its content during processing. One knowledge base can contain a Finnish manual and an English price list, for example. Retrieval rules follow the detected language, so an incorrect language label can reduce search quality.

Finnish retrieval rules help find inflected forms of a word. Matches still depend on the question and source content; test expressions your customers use.

Search-language editing is not available in the same way for every source. If the source details provide an enabled **Language** choice, select Finnish or English and wait for save confirmation. Test retrieval again. If the choice is missing, disabled or fails to save, do not try to bypass the restriction: [contact us](/en/contact#contact-form) with the source type and expected language.

The **fallback language for new sources** (Settings → Languages) is used only when a source's own language cannot be determined. It does not override detection or a manual correction.

## What actually happens: examples

### Reply language is Always English and the customer writes in Finnish

1. **Search language is assessed from the question.** An English reply setting alone does not change a Finnish question's retrieval language.
2. **The reply is instructed to use English.** The fixed reply setting overrides automatic selection.
3. **Follow-up questions are instructed to use English.** Check their language too if the feature is enabled.
4. **The widget interface does not change** — that is its own axis.

You can therefore test English replies from a Finnish knowledge base. Check names, numbers and terms of service in particular; a language setting does not guarantee their correct interpretation.

### Reply language is Automatic and the customer writes in German

The agent can reply in German. Retrieval uses semantic search, but the Finnish and English language-specific search rules do not apply to German. Review answer quality yourself.

### The visitor's browser is English and only Finnish is on the list

The widget interface appears in Finnish. The reply language is decided separately by its own setting.

### A visitor switches the language from the menu

Only the interface language choice changes. The reply setting stays the same: an agent fixed to Finnish is still instructed to reply in Finnish even when the visitor reads an English interface.

## When to change what

| Situation                                                                    | Change this                                       |
| ---------------------------------------------------------------------------- | ------------------------------------------------- |
| Customers write in several languages and you want to serve each in their own | Reply language → Automatic                        |
| You want the bot to always reply in your company's language                  | Reply language → Always Finnish or Always English |
| Visitors who speak other languages use your site                             | Add a language to the widget language list        |
| The bot inflects product or authority terms incorrectly                      | Protected terms (Settings → Languages)            |
| Search does not hit a source as expected                                     | Check that source's language in Knowledge         |