Browser-based OPI simulator: 5-stage oral interview with TTS prompts, ASR transcription, and a 5-dimension heuristic ILR estimate. No signup, no upload, all local.

What is the OPI?

The ACTFL Oral Proficiency Interview is a 20–40 minute one-on-one speaking interview administered by a trained rater. It is the standard speaking-proficiency assessment used by US government agencies — FSI (Foreign Service Institute), DLI (Defense Language Institute), Peace Corps — to certify second-language speaking ability. Unlike IELTS or TOEFL, the OPI does not grade grammar or read-aloud. It grades what tasks you can sustain under pressure: can you describe your job in paragraphs? Can you argue a position? Can you sustain a role-play in an unfamiliar situation? Those tasks map to ILR levels 1 through 5.

This simulator runs that protocol in your browser. TTS asks the question, your microphone records, browser ASR transcribes, and a 5-dimension heuristic produces an ILR estimate. No data leaves your machine.

The 5 stages, in order

The OPI uses a fixed protocol with five stages. A trained rater calibrates the difficulty in real time; the simulator approximates this by reading your baseline ILR (from the self-assessment) and routing Level Check + Probes accordingly.

Warm-up (3 questions, unscored)

Could you tell me your name, where you're from, and what you do?
What did you do earlier today, before this conversation?
What's something you enjoy doing on weekends?

Level Check · ILR 1 tier

Describe the place where you live. What does the neighbourhood look like?
Tell me about your family. Who lives with you?
What did you eat for dinner last night? Walk me through it.

Level Check · ILR 2 tier

Tell me about your last vacation or a memorable trip. What happened day by day?
Describe your current job or studies. What do you do on a typical day?
Tell me about a time something went wrong and how you solved it.

Level Check · ILR 3 tier

Compare two cities or two cultures you know well. Where do they differ and why?
Pick a current event from this week and summarise it. What's your view on it?
Walk me through a recent decision at work or in your studies. What were the trade-offs?

Level Check · ILR 4 tier

If you were briefing a foreign delegation on a policy issue you know well, how would you frame it?
What's an idea from your field that's underappreciated, and how would you defend it to a sceptic?

Probes · ILR 1 tier (one above the level-check tier)

Tell me about a goal you have for the next year. How will you reach it?
If a friend visited your country for a week, what would you recommend they see and do?

Probes · ILR 2 tier (one above the level-check tier)

Argue for or against this: 'remote work is better than office work'. Support your view.
Describe a problem your country or city is facing, and what would you do about it.

Probes · ILR 3 tier (one above the level-check tier)

How might artificial intelligence change your industry in the next five years?
What's a policy in your field you would change, and what trade-offs would that involve?

Probes · ILR 4 tier (one above the level-check tier)

What's a complex ethical dilemma in your field where reasonable people genuinely disagree?

Role-play scenarios (1 chosen at random per session)

Lost luggage at a foreign airport · 4 turns

Open the conversation with the airline agent and explain what happened.
The agent asks you to describe your bag and its contents in detail.
Ask what your rights are and what happens next.
Close the conversation by negotiating a way to be reached when the bag is found.

Job interview follow-up · 4 turns

Open with a polite greeting and remind the interviewer who you are.
They ask why you should be hired over the other candidates.
They raise a concern about a gap in your experience. Address it.
Close the call by setting an expectation for next steps.

Wind-down (self-reflection)

Was there anything during this conversation you wanted to say but couldn't find the words for?
What's one thing you'll work on after this conversation?

How the scoring works

Five dimensions, each rated 1–5 stars from your transcribed answers:

Fluency — words per minute averaged across answers. 80 wpm ≈ ILR 2, 130+ ≈ ILR 3.
Vocabulary — type-token ratio (unique words ÷ total words) over the whole session.
Completion — how many of the 5 stages have at least one captured answer.
Endurance — average response duration in seconds. ILR 2 expects 30+ s answers; ILR 3 expects 60+ s.
Level reach — the highest probe tier you attempted, regardless of how well.

The mean of these five maps to ILR 1 / 1+ / 2 / 2+ / 3 / 3+. Thresholds are deliberately conservative so the simulator does not inflate estimates. None of these proxies are perfect — a slow but deep speaker is undervalued; an articulate-sounding learner who avoids hard topics is overvalued. Use the result as one data point, not a verdict.

What this simulator cannot do

A real OPI rater can probe in real time: when you make a strong statement, they push you to defend it; when you flounder, they back off to confirm where the ceiling is. A scripted question bank cannot do that. Treat this tool as a training-camp baseline and a mental rehearsal, not a certification. The closest free interactive replacement we know of — but still not a replacement.

Free OPI Simulator (ACTFL-style Oral Proficiency Interview)