24.16. Languages

Conversational AI supports the following languages for both voice and digital:

• English

• German

• Dutch

In order to change which language you’d like CAI to operate in you will need to update the Language settings on the Persona from the Routing policy before your AI Apps.

Configuration

Ensure you have added a Persona App before connecting to the Assistant or Agent App, then click onto the Language tab and you’ll have the following settings:

Quick Start

1. In the Persona app → Language tab, tick Set Initial Language and pick a language.

2. Choose a Default Voice that matches that language.

3. (Optional) Enable Auto‑Detect Language so we pick the appropriate language based upon the country associated with the numbers calling in (if available)

You’re up and running.

Write Prompts in English

All system, Agent and Assistant prompts should remain in English. This is because the AI model is predominantly trained in English and hence will provide better and more reliable results.

All language translations are automatically handled by the AI on the fly, allowing customers to communicate in their own language.

Welcome/Success messages

All welcome and success message that the AI reads out to the customer will be automatically translated into the language defined in the Persona, even when using free-form [INSTRUCTION: …] instead of fixed text

If you’d rather set your own translations for specific messages you wish the AI to communicate to your customers you can use a Response App and check the option ‘Response with the exact text in the User response prompt’.

Voice management (picking the right voice)

Use the Persona app to choose voices per language (and where available, per dialect):

• Naturalness first → Pick a voice designed for that language; pronunciation and intonation will be best.

• Consistency first → Use one voice across languages; pronunciation may be less native, but the voice won’t change.

• If no voice is set for a language/dialect, we fall back to your org default voice.

Design the experience you want: smooth single‑voice vs. most‑natural per‑language.

Normalization Prompts (make speech sound native)

Normalization Prompts tidy up text before outputting via the Voice. Numbers, dates/times, currency, units, addresses, phone numbers, and more—so speech sounds right in each locale.

Why it matters Different locales say the same string differently:

• US English (MM/DD/YYYY) 01/02/2025 → “January second, twenty twenty‑five”.

• GB English (DD/MM/YYYY) 01/02/2025 → “the first of February, two thousand and twenty‑five”.

System vs. Custom Prompts

• System Normalization Prompts – Provided for every supported language. Find them in Natterbox Settings → Voice Normalization Prompts (read‑only, so you can see what’s covered).

• Custom Normalization Prompts – Add your own rules for brand terms, SKUs, part codes, etc.

Create a custom Normalization Prompt

1. Go to Voice Normalization Prompts → New.

2. Choose Language and (optionally) Region/Dialect (e.g., en, en-GB, de-DE).

3. Start your prompt with <<SYSTEM_NORMALIZATION_PROMPT>> to inherit the baseline rules.

4. Add small, example‑driven sections. For example:

5. <<SYSTEM_NORMALIZATION_PROMPT>>
   #PART CODES#
   "Part# ABC-123" -> "Part number A B C dash 1 2 3"
   "Component:PDQ52DEF" -> "Component P D Q 5 2 D E F"

6. Save and (optionally) Set as Default for that language/dialect. If you do, Personas use it automatically unless they explicitly pick another prompt.

Selecting prompts in the Persona app

To use Speech Normalization, you just need to enable it in the Persona App.

1. To enable the feature, simply turn on Speech Normalization in the Persona App (Language tab).

2. By default, the AI platform will automatically select the default Normalization Prompt corresponding to the language being spoken by the AI.

3. If you need to override the default for a specific language, you can create language-to-prompt mappings in the Persona app.

Best Practice: Most of the time, you should only need to enable normalization and rely on the system defaults.

Agents

If you’re building your own Agents, you’ll need to ensure your Agents are configured to support languages and a Persona App has been set otherwise they will default to English.

Language Macro

In order to use non-English languages with your Agents just drop in the macro $(AILanguageInstructions) into the Agent Goal Prompt.

We recommend to add this at the end of the Agent Goal Prompt, normally just before the {{_CURRENT_DATE}} to ensure that prompt caching can be maximised.

It expands to:

## LANGUAGE INSTRUCTIONS ## 
Respond entirely in the language named in <language_context> -> Language. Do not use or infer any language code. 
Output rules: 
- Write the entire reply in that Language. 
- Follow that Language's conventions for numbers, dates, currency, and punctuation. 
- Do not translate code snippets, keys/IDs, placeholders {like_this}, URLs, or brand/product names. 
- Keep emojis, casing, and tone consistent with the input/context.