Teach your mouth the language
your brain already knows.
You already know the language. Now say it out loud — the interview, the dinner, the client call. Sierra listens, corrects your pronunciation, and hands back the phrase a fluent speaker would've used. In 97 languages, on any topic.
Loved by employees at
Anthropic
Vercel
Airbnb
Meta
Your tutor for every
conversation this week.
tutor for everyYou pick the scene. Your tutor plays it — in your target language — and tells you exactly what to fix when the session ends.
Describe it. Sierra builds it.
Any conversation you can think of — in any language. Sierra builds the tutor for it: the voice, the questions, the pushback, the feedback. All made for you.
- A PM interview at Google
- A system design round in English
- A client call in French
- A TOEFL task with a strict examiner
- A salary talk you've been putting off
Feed it context — a YouTube talk, a
Notion page, a PDF of the rubric. Sierra reads it all and writes the tutor around that material: a persona with the right background, an opening line in your target language, and a feedback framework that knows what good looks like.
No templates. No canned prompts. Describe it — and start speaking in under a minute.
New skill
What do you want to call this skill?
Google PM Interview
Who plays the interviewer?
A senior PM — direct, metrics-driven
Drop any sources — YouTube, websites, PDFs.
Crafting the system prompt…Three steps to confidence.
No textbooks, no flashcards. Just a tutor who speaks back, in character, and tells you exactly what to fix.
Pick your scenario
Café in Rome, job interview in English, a TOEFL task. Pick a ready-made one or describe the conversation you're trying to own — your tutor shapes around it.
Speak with your tutor
Open your mouth and speak — in any of 97 languages. Your tutor stays in character, listens closely, and interrupts exactly where a fluent speaker would.
Learn from every slip
Every mistake becomes a correction, an explanation, and the phrase you'd have used if you were already fluent. Session by session, the vocabulary sticks and the hesitation shrinks.
Rehearse with .
The mistakes make you fluent.
You learn by stumbling. Sierra catches every slip, teaches you why, and hands you the phrase you'd have used if you were fluent. Session after session, your vocabulary stretches and the hesitation shrinks — until the topic is yours.
The presentation was, uh, good I guess? People seemed to like it.
Hedging steals the win. State it flat.
Corrections
Hedge reads as doubt. In an interview, you know.
Suggestions
• Open with the result, not the uncertainty.
• Point to a signal — applause, questions, a follow-up.
Alternative ways to say it
“The presentation went well — we took 15 minutes of questions and the CEO asked for a copy of the deck.”
Send a full session to your tutor, your teacher, anyone who's rooting for you.
Every slip teaches something.
No panel, no grade — just the tutor, the lesson, and you trying again.
Last session you hedged on numbers; this one you committed. The next one, it's going to feel like English.
Answers
Tighter than last time — less qualifying.
Confidence
Steadier with numbers. One step from flat.
Tense accuracy
Past solid. Present perfect clicked mid-way.
Follow-ups
Four for four — a new high for you.
Questions & answers
Sierra is an AI-powered conversation practice platform. Practice client meetings, team standups, job interviews, language exams, networking, and everyday conversations with AI partners that listen and respond in real time — in 97 languages.