Teach your mouth the language
your brain already knows.
You know more English than you use. Sierra turns your goals into specialist tutor notebooks, listens while you speak, and turns every session into vocabulary, drills, and the next thing to practice.
Loved by employees at
Anthropic
Vercel
Airbnb
Meta
Your notebook for every
conversation this week.
notebook for everyYou pick the English context. Sierra creates the specialist tutor and tells you exactly what to improve when the session ends.
Describe it. Sierra builds it.
Any English conversation you need. Sierra builds the notebook for it: the tutor behavior, scenarios, voice practice, pushback, feedback, and drills.
- A PM interview at Google
- A system design round in English
- A difficult client call in English
- 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 builds the notebook around that material: the right context, a specialist tutor, opening questions, 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 notebook
What do you want to call this notebook?
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 classroom dashboard. Just Sierra routing, practicing, and showing what to improve.
Start with Sierra American
Tell Sierra the English situation you want to improve. Sierra checks memory and existing notebooks before creating another specialist tutor.
Speak with a specialist tutor
Speak in English inside the selected notebook. The tutor keeps the practice tied to that outcome and your active vocabulary.
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 a coach, teacher, anyone who's rooting for you.
Every slip teaches something.
No panel, no grade — just the answer, 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 English tutor orchestrator. Start a new thread, tell Sierra what you want to improve, and Sierra routes you into a diagnostic or a specialist notebook for repeated speaking practice.