TRAI AI Coach in 26 Languages: How It Works

Which languages does TRAI, Trainera's AI coach, speak?

TRAI, the AI assistant built into Trainera, replies in your app language and mirrors the language you write in. In October 2026 the Trainera app and the plans TRAI builds come in 26 languages: 25 languages, with Serbian in both Cyrillic and Latin script. That covers Bosnian, Croatian, Serbian and Montenegrin as separate languages, German, Arabic (Modern Standard Arabic) and most of Europe.

This post explains how TRAI chooses a language, how a trainer gets a plan written in a client's language, how gym owners are addressed formally, and where the limits are.

The 26 language codes TRAI and the app use

Every language below is both a dashboard language and a language TRAI can write a plan in.

The codes follow the usual language tag convention described by the W3C guide to language tags: a two-letter code from ISO 639, plus a script subtag where one language has two alphabets (sr-Cyrl, sr-Latn).

Count them and you get 26 codes for 25 languages. Serbian appears twice because it is written in both alphabets, and a plan in the alphabet a reader does not use every day feels foreign.

How TRAI decides which language to answer in

TRAI starts from the language set in your account and then follows the language you actually write in.

In practice that gives three cases:

• You write in your app language. The reply comes in that language. A trainer with the dashboard in Croatian who writes in Croatian gets Croatian back.
• You write in a different language. TRAI mirrors you. If your app is set to English but you type in Bosnian, the answer comes in Bosnian.
• You use the mobile app. The language comes from the language stored on your account, so web and phone behave the same way. Chats are stored on the server, so the same conversation shows on both.

Example prompt (Bosnian): "Napravi mi plan za 3 dana u sedmici, imam samo bučice i trake."

Example prompt (German): "Wie viele meiner Kunden haben diese Woche kein Training eingetragen?"

Both are examples of how people actually write: short, in their own language, with no special syntax. You do not need to switch the app language to get an answer in another one.

Can a trainer get a client's plan in a different language?

Yes: the plan language defaults to the trainer's own language, and the trainer can name another one in the request.

This matters for coaches who work across borders. A trainer in Sarajevo with clients in Vienna, or a coach in Dubai with English and Arabic speakers, writes to TRAI in whatever language is comfortable and asks for the plan in the client's language.

Example prompt: "Build a 4-day upper/lower plan for Lena, intermediate, full gym, and write the plan in German."

Example prompt: "Napravi plan ishrane za Amira, 2.400 kcal, 4 obroka, halal, i napiši ga na arapskom."

The plan engine behind TRAI is the same one as the app's Generate buttons. The AI writes a structured prescription and a deterministic engine assembles the plan from Trainera's library of more than 1,800 exercises with images and videos. The trainer's own exercises and meals are picked first. So the language request changes the text of the plan, not where the exercises come from.

For nutrition plans built for a client, the engine also adds the client's goal, medical conditions, allergies, dietary preferences and body stats from their profile. Profile allergies are always added, never dropped, whatever language the request was written in. The sibling post on stating dietary rules for AI meal plans goes deeper on that part.

Does TRAI understand equipment and injuries in my language?

Yes. The training engine has its own vocabulary for 26 app languages.

That vocabulary covers warm-up, stretching, cardio, implements (machine, barbell, EZ-bar, dumbbell, kettlebell, band, bodyweight, pull-up and dip bar), negations, body parts and injuries. Negations are the important bit: "no barbell" has to remove the barbell, not add it.

Example prompt (Croatian): "Bez šipke i bez skokova, koljeno me boli. Kardio na kraju, istezanje na kraju."

Example prompt (Dutch): "Alleen elastieken en een kettlebell, 30 minuten, eerst opwarmen."

Sessions are built in a fixed order: cardio at the start if asked, warm-up, main work, cardio at the end if asked, and stretching. You can ask for that order in any of the 26 languages. The sibling post on equipment constraints lists the equipment options.

Formal address for gym owners: Vi and Sie

TRAI addresses gym owners formally in every language that has a formal form, such as Vi in Bosnian, Croatian, Serbian and Montenegrin, and Sie in German.

That is a deliberate rule in the gym version of TRAI, because a gym owner reads it as a business tool. When TRAI is opened from Automations ("Ask AI"), it is told the same thing explicitly: formal Vi in bs, hr, sr and me, Sie in de, as the app does. It also keeps to the app's language, dialect and script for the whole reply, so a Cyrillic app language means a Cyrillic reply, unless the owner clearly writes in another language.

Automation messages themselves can carry several languages. You can ask TRAI to add a translation to an automation's messages, and a step that has a formal text keeps its formal version too.

Example prompt: "Add a German version to the welcome automation, formal."

See building automations by chat for which plans include Automations AI.

Who gets TRAI in their language

Language support is the same for every role, but access and monthly allowance are not.

Trainer plans start at $19.99 a month for Starter, $49.99 for Pro and $99 for Business; Client Pro is $5.99 and Premium $6.99. Those are US-dollar prices; prices differ by country on trainera.fit/pricing. The sibling post on TRAI request limits explains what one request covers.

What language support does not cover

TRAI has no voice input, so you type in your language rather than speak it.

• No PDF reading. On web you can attach text files, .docx and images (up to 4 files, 5 MB each). A PDF is refused with a request to upload .docx or .txt instead. On mobile you can attach images only.
• Images are read with vision. A photo of a handwritten plan or a menu in Bosnian or Arabic is transcribed and described, but handwriting quality still matters.
• Mistakes happen. The chat footer says it plainly: "AI can make mistakes. Double-check important results." For a plan in a language you do not read yourself, ask the client to flag anything unclear.
• It is not a medical service. The plan engine adapts to injuries and pregnancy, choosing low-impact work, but in any language that is no substitute for a doctor.

One more practical limit: TRAI remembers the newest 40 messages of a chat on each turn. If you switch language halfway through a long chat, the earlier part still counts as context, but very old messages fall out.

Tips from coaching across languages

Most language problems come from vague requests, not from the AI.

1. Name the plan language when it differs from yours. "Write the plan in Macedonian" is clearer than hoping TRAI guesses from the client's name.
2. Pick the Serbian script on purpose. Say "Serbian, Latin script" or "Cyrillic" so the client gets the alphabet they read daily.
3. Keep food words local. "Grah", "burek" or "labneh" said the way the client says them gives a better match than a translated guess.
4. Write injuries in plain words. "Left knee hurts on stairs" works in any of the 26 languages; you do not need medical terms.
5. Check one plan per new language yourself before you send many, then build on what worked.

Coaches who work mostly with German or Arabic speakers can compare the wider app side in the app guide for German-speaking clients, the Arabic AI coach guide and multilingual fitness apps for trainers.

How to try TRAI in your own language

The fastest test is one real request in the language you coach in.

A trainer opens TRAI on a paid plan and writes one message: a client, a goal, the equipment and the plan language. A solo client on Client Pro or Premium asks for a plan in their own words. A gym owner asks a question about members or leads in the dashboard's language and gets a formal answer. If the first reply is in the wrong language, write the next message in the one you want and TRAI follows.

New trainers can create a trainer account and switch the dashboard to any of the 26 languages before upgrading.

See what Trainera's AI tools do for clients on the AI fitness coach page.