I've tried it both ways.
You can ask Apple's thing a construction question. Different phrasings. Different speeds. The answer comes back and it's wrong — not approximate, not off by a rounding error. Wrong. It either doesn't know the formula or it doesn't know the word. Or both. "How many studs for a 20-foot wall" returns a web search result for a structural engineering firm in Phoenix. "Rafter length for a 6/12 pitch, 20-foot run" gets you a Wikipedia article about roofing history.
The question isn't hard. Any framer could do it on a napkin. But try asking your phone and you'll find out quickly: your phone has no idea what a pitch is.
Voice assistants are designed for the most common question. And the most common question isn't what happens on a job site. They can get you a restaurant reservation, give you the weather, settle an argument about a movie. But "how much concrete for a 24-inch round column, 4 feet deep" isn't anywhere on their map of likely human intentions.
So you either slow down, pull out your construction calculator, and try to remember the formula — or you Google it and hope the result gives you something in fractions. Most of the time, it's decimals.
The math is simple. It's the interface that's wrong.
A construction calculator should understand how you speak on the job. Not how you'd phrase a question to a voice assistant trained on recipe searches and weather queries. Not how a math professor would write it. How you actually say it when your hands are full, you're three steps into a mental sequence you don't want to lose, and you need the answer in about three seconds.
"How many studs for a 20-foot wall." Not "calculate stud count for a 20-foot wall with 16-inch on-center spacing." The question. The way you'd ask it to the guy next to you.
That's the design problem. And it turned out to be harder to solve than the math.
The STT Problem
Speech-to-text makes it worse before voice assistants even get to process it. It hears "6/12 pitch" as "six twelve pitch" or "612 pitch" or, on a rough day, something phonetically adjacent but entirely different. It hears "2x6 framing" as "to buy six framing." Once the input is garbled, the whole thing fails — unless the system is built to expect that construction terms will come through mangled and to recognize them anyway.
You say: 'How many studs for a 20-foot wall at 16 on center'
STT hears: 'How many studs for a 20 foot wall at sixteen on center'
Generic voice assistant: returns a web search
Journeyman: returns '16 studs' in under 3 seconds
We built recovery rules into the parser — not a lookup table of correct spellings, but rules that account for how speech-to-text systems predictably mangle trade vocabulary. "Stud" becomes "stood" or "stud." "On center" becomes "on center" or "unsenter." The patterns are predictable. The recovery catches them.
The result is an app that understands the question even when the microphone didn't quite catch it. And it comes back with the answer in fractions — 1-3/4", not 1.75 — because that's what fits on a tape measure.
155 formulas. 18 trade categories. Everything accessible by voice, in the language you'd actually use on the job.
Journeyman Voice Calcs is available now on the App Store.