Quick Answer
No general English app teaches the English of a code review, a stand-up or a system design round, so pick by gap. Duolingo or Busuu for grammar and vocabulary basics; Speak, Praktika, Loora or Talkpal for daily speaking; ELSA Speak or BoldVoice for pronunciation; and Mockly English's free Mini Apps for technical English (explaining LeetCode, system design and STAR stories out loud). When an interview is coming, Mockly's engineer-coaches run the round with you in English and fix what you say.
What makes Mockly English different
Mockly English is built for one job: getting non-native engineers and data professionals through tech interviews, and through meetings, in English. Your coach is a practising UK data engineer who also teaches English. They run the real round (coding, system design, SQL and data, behavioural, HR), then correct your English line by line and have you say it again. The first 30 minutes are free with no card; after that it is $50 a session, with no subscription.
⚡ Quick Stats
The English Engineers Actually Use
Most English apps teach travel, small talk and everyday grammar. An engineer working in English needs a narrower, harder set of skills:
- Explaining while thinking: narrating code, a bug or a design as you work it out.
- Trade-off language: “we could cache this, but then we have to handle invalidation”.
- Short status updates: what you did, what is blocked, what you need.
- Polite disagreement in code reviews and design reviews.
- Interview stories: STAR answers that say “I”, not “we”, and sound like your level.
General apps help with the foundation under all of this: vocabulary, grammar and the confidence to speak. None of them we checked has lessons on narrating code or system design. That is the gap the last group below fills.
The Best Apps, by Gap
| Your gap | App | What it does | Price (as checked) | Read more |
|---|---|---|---|---|
| Grammar and vocabulary basics | Duolingo | Free bite-sized lessons in reading, writing, listening and speaking; Super has a 1-week free trial | Free core app; Super price not shown on its page | Mockly vs Duolingo |
| Grammar and vocabulary basics | Busuu | Courses from A1 to C1, feedback from fluent speakers in its community; Premium Plus adds AI conversations | Free to start; paid plans on sale when checked | Mockly vs Busuu |
| Daily speaking | Speak | Speaking-first AI app with real-time feedback on pronunciation and phrasing; custom lessons (beta) can cover interview questions | 7-day free trial; price in the app | Mockly vs Speak |
| Daily speaking | Praktika | AI avatar tutors that correct pronunciation, grammar and word choice as you talk | About $8/month (homepage) | Mockly vs Praktika |
| Daily speaking | Loora | AI speaking partner with Business English modules for interviews, meetings and presentations | US App Store: $14.99–$19.99/month | Mockly vs Loora |
| Daily speaking | Talkpal | AI tutor on web and mobile; speak or write, get voice replies and feedback | Free plan with limits; Premium price not shown | Mockly vs Talkpal |
| Pronunciation | ELSA Speak | Pronunciation scoring at the sound level | Free tier plus paid subscription | Mockly vs ELSA Speak |
| Pronunciation and accent | BoldVoice | Video lessons from accent coaches plus AI feedback on sounds, stress and clarity | 7-day free trial; US App Store from $14.99 | Mockly vs BoldVoice |
| Technical and interview English | Mockly Mini Apps | Explain LeetCode and system design out loud, STAR builder, filler-word drill, tell me about yourself | Free, no account | Try one |
Facts come from each app's own site or US App Store listing, checked between 24 October and 10 November 2026. Several apps ran sales when we looked, so check the price in the app.
Apps for Technical English
These free Mockly English Mini Apps work in the browser with no account. Each one is built around a moment in a tech interview or a tech job.
- Explain LeetCode in English: say your approach, an example and the complexity, then get feedback on the English. There are problem-specific versions, such as Two Sum and LRU Cache.
- Explain system design in English: walk through requirements, components and trade-offs in a clear spoken order.
- STAR builder: turn a work story into a STAR answer that sounds like you, in natural English.
- Filler-word killer: catch the “um”, “like” and “basically” that make answers sound unsure.
- Interview pronunciation coach: the tech words non-native speakers most often mispronounce. See also -teen vs -ty.
Free Mini App
Explain a LeetCode solution out loud
Pick a problem, say your approach in English, and see which phrases to change. Free, no account.
Try the Mini AppA 15-Minute Daily Stack
- 5 minutes: one general app for vocabulary or pronunciation (Duolingo, Busuu, ELSA or BoldVoice), whichever matches your weakest area.
- 5 minutes: speak with an AI tutor (Speak, Praktika, Loora or Talkpal) about your actual work: yesterday's bug, today's ticket.
- 5 minutes: one Mockly Mini App: explain one problem or one design out loud.
Talking about your real work is the step most people skip. It turns general English into the English you need in a stand-up or an interview.
When an App Is Not Enough
Apps are good for the foundation. They stop helping when you need someone to judge a whole answer: whether your design works, whether your story sounds senior, whether a phrase means what you think it means. If you have an interview loop in the next month, or you freeze in English meetings, a human is quicker.
Mockly English coaches are practising data engineers who also teach English. A session is a real round (or a real meeting scenario) followed by line-by-line corrections. Start with the free 30-minute trial. For a wider view of interview practice options, see best mock interview platforms for non-native speakers.
Mockly prices (as of November 2026)
- Mockly: a free 30-minute trial with a coach on Google Meet. No card and no subscription.
- Mockly: live 60-minute 1:1 sessions are pay-as-you-go. One session is $50; packs of 5 ($237.50), 10 ($450) or 20 ($850) cost less per session. Credits last 12 months and work with either coach.
- Mockly: Premium is the self-study course at $9.99/month, or $59.99/year, with a 7-day free trial. It does not include a coaching session and you do not need it to book one.
Verdict
Use one general app for your weakest basic skill, one AI tutor for daily speaking, and Mockly's free Mini Apps for technical English. Add a live coach when an interview is close.
Talk to an engineer-coach first
Book a free 30-minute Google Meet with Sophie or Tom. No card, no subscription. You practise a short interview-style prompt in English and leave with a plan for what to work on next.
Book a Free Trial →