Practice technical English for engineers

Engineers rarely struggle with technical vocabulary — you read it every day. The struggle is spoken: explaining a design decision to a client, reporting a problem on site without sounding alarmed, pushing back on an unrealistic deadline, or presenting a status update to management in plain English.

Airi plays your client, project manager, or contractor so you can rehearse these conversations out loud. Practice explaining a technical issue simply, walking someone through a drawing or a process, and negotiating scope and timelines. The clearer you are in English, the more your expertise is trusted.

A quick example with Airi

I'm the client. Why is the foundation work taking longer than planned?

We found that the soil condition is different from the survey, so we need to make the foundation deeper.

Small fix: "the soil conditions are different from the survey." Clear. How much delay are we talking about?

About two weeks. I will send a revised schedule tomorrow with the new cost.

"I'll send a revised schedule." Good — direct, no panic. That builds trust.

Try a conversation like this, free600 free credits, about 8 minutes of speaking. No card.

How engineers say numbers, units and tolerances in English

Saying a dimension on a call is a separate skill from reading it on a drawing, and a misheard number can be an expensive mistake.

On the drawing	Out loud
0.05 mm	zero point zero five millimeters
50 ± 0.1 mm	fifty millimeters, plus or minus zero point one
300 × 600 mm	three hundred by six hundred millimeters
Ø 25 mm	twenty-five millimeters in diameter
Scale 1:50	a scale of one to fifty
12 m³	twelve cubic meters
5 kN/m²	five kilonewtons per square meter
90 N·m	ninety newton meters
3/8 in.	three-eighths of an inch

After the point, say each digit on its own: 3.25 is "three point two five", never "three point twenty-five". Say "point" even if your language writes a comma. NIST's Guide for the Use of the International System of Units (SP 811) recommends the dot as the decimal marker in the United States and notes that the comma is widely used as the decimal marker elsewhere. That is why "1,250" can be read two ways on an international project: as one thousand two hundred fifty, or as one and a quarter. If a figure matters, repeat it digit by digit and say the unit.

Phrases engineers need in design reviews, site meetings and handovers

When you have to	What it sounds like
Point to a detail on a drawing	If you look at section B-B, the dashed line shows the pipe running behind the wall.
Flag a conflict between documents	The drawing shows a 200-millimeter slab, but the spec says 250. Which one takes precedence?
State a limit	The base plate has to be level to within two millimeters.
Push back on a date	The test rig is booked until Thursday, so Friday isn't realistic. I can commit to next Wednesday.
Stop unsafe work	Stop work, please. That scaffold hasn't been inspected yet.
Hand over at shift change	Pump two is locked out. Don't restart it until the seal has been replaced.
Read an instruction back	So, to confirm: torque all eight bolts to ninety newton meters.

What "shall", "should", "may" and "can" mean in an engineering standard

ISO and IEC standards use four small verbs with fixed meanings, and mixing them up can turn a recommendation into a requirement. The definitions come from the ISO/IEC Directives, Part 2, the rules for drafting those standards.

In the standard	It expresses	In a meeting
shall	A requirement	The standard says the welds shall be inspected, so we can't skip that step.
should	A recommendation	It only says both ends should be labeled. That's recommended, not required.
may	Permission	It says either grade may be used, so both are permitted.
can	A possibility or a capability	It says the valve can be mounted in any position. That tells us what's possible, not what's required.

The same rules reserve "must" for constraints from outside the document, such as a law of nature, and tell drafters not to use it in place of "shall". Other standards bodies and your contract may define these words differently, so check the definitions in the document you are working to.

English verbs for describing an equipment fault

"It's broken" gives a maintenance team nothing to work with. English has a specific verb for most kinds of failure.

A circuit breaker trips, and a fuse blows.
A bearing or an engine seizes up when its moving parts lock.
A bolt shears off. A weld or a slab cracks.
A seal leaks, and a filter clogs.
Steel corrodes. A belt wears out.
A motor overheats. A sensor drifts out of calibration.

Then add when and under what conditions: "The breaker tripped twice this morning, both times when the second pump started."

Common English mistakes in engineering meetings and reports

Instead of	Say	Why
It's a 50-millimeters pipe.	It's a 50-millimeter pipe.	A measurement placed before a noun stays singular: a six-meter beam, a ten-kilowatt motor.
The tolerance is more or less 0.1 millimeters.	The tolerance is plus or minus 0.1 millimeters.	"More or less" means "roughly". The ± sign is read "plus or minus".
I'll send the revised drawing until Friday.	I'll send the revised drawing by Friday.	"By" sets a deadline. "Until" describes something that continues up to a time: "The crane is on site until Friday."
The damages to the pipe are serious.	The damage to the pipe is serious.	"Damage" is uncountable, like "equipment". "Damages" is the legal word for money a court orders someone to pay.

An eight-minute engineering rehearsal to run with Airi

The free credits last about eight minutes of speaking, so have one real drawing in front of you to read from and keep each step short.

Set the scene: "You are the site manager at our weekly progress meeting. Ask for my update, then question my numbers."
Read five dimensions aloud with units and tolerances, then ask: "Please repeat those numbers back to me." If one comes back wrong, say it again more slowly, digit by digit.
Change the listener: "Now you are the client's finance director, not an engineer. Ask me why we need the more expensive option." Answer without jargon.
Report a fault with the exact verb, then hand over: "You are taking over my shift. Ask me what you need to know."
Treat each small fix she shows you like a redline on a drawing: say the corrected sentence once, then keep going.

How to get the most from it

Explain simply

Practice describing a technical problem to a non-engineer in three plain sentences.

Report problems calmly

Rehearse the structure: what happened, impact, what you'll do. Airi plays the worried client.

Drill meeting phrases

"Let me clarify", "The risk here is...", "I'd recommend..." — make them automatic.

Start speaking today

Your first 600 credits are free — no credit card. Sign in and have your first conversation with Airi.

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Frequently asked questions

Which engineering fields does it suit?

Any: civil, mechanical, electrical, software, oil and gas. Describe your project and Airi plays the relevant stakeholder.

Does Airi understand technical terms?

Usually. She follows the common vocabulary of most engineering fields and helps you explain it clearly to others. If she mishears a rare term, a product name or a part number, say it again slowly or spell it out.

How do I say dimensions and tolerances in English?

Read × between dimensions as "by", ± as "plus or minus", and every digit after the decimal point on its own: "fifty by twenty millimeters, plus or minus zero point two five."

What is the difference between "shall" and "should" in a specification?

In standards drafted under the ISO/IEC Directives, "shall" marks a requirement and "should" marks a recommendation. "May" gives permission, and "can" states a possibility or a capability.

Should I use British or American engineering terms?

Use the terms in your project's drawings and specifications, and learn to recognize both. A British "spanner" is an American "wrench", "earth" on a British electrical drawing is "ground" on an American one, and British "aluminium" is American "aluminum".

Is it free to try?

Yes. Signing up with Google gives you 600 free credits, about eight minutes of speaking, with no credit card. That is enough for one quick run through the rehearsal above. After that, credits come in one-off packs: USD 5, 10 or 20 for 2,600, 7,200 or 17,000 credits. There is no subscription.

Last updated: 2026-10-03