So the other day I was talking to a friend (he's a native speaker by the way). We were talking about a certain subject when I said "How do you call that Gerry?", How do you say when someone is doing this or that and etc..." And every time I'd use "How" he would correct me and say it's "What" not "How", "It's what do you say, what do you call". Why was I wrong? I think many people don't know this.
When asking how to refer to something or someone in English, the most conventional form is to ask
What do you call X?
Call in the sense of identifying someone or something by a name or term is a complex transitive verb, in that it requires both a direct object and an object complement to communicate the meaning. The someone or something being identified is the direct object, and the name or term is the object complement. When asking a question with call, you are asking what the name or term is.
A fixed layout shows the same layout regardless of screen size, and a fluid layout stretches or shrinks the same layout proportionately. What would you call a layout that changes depending on screen resolution?
Our baby girl is only three years younger than my brother Jack.
Oh? What will she call him, Jack or Uncle Jack?
There is an entire genre of punny jokes based on this pattern.
What do you call a man who's always asking for money?
If asking about phrasing for translation (whether to another language or to specialized terminology), you could instead ask
how do you say X
Here, you are not asking for a term or name, but for a manner, thus the interrogative is how rather than what.
How do you say "I think you are very beautiful" in Tswane?
How would you say you want to be paid within 90 days for a contract?
I think these two, and perhaps others, get conflated among some learners. Also, how do you call would be the literal translation of the same question in various other languages, notably Romance languages, e.g. ¿Cómo se llama esto? Like saying touristic, however, it is a distinct marker of an ESL/EFL speaker.
Another form you may come across is how to say X, something I have used myself in forum thread titles, for example. I would not actually say this, or use it in most writing, even informal writing. In a title, however, it would be understood to stand for could someone instruct me how to say X or I would like to know how to say X.
A quick look at a dictionary should really be all you need. The primary meaning of 'what' is "interrogative expressing inquiry about the identity, nature, or value of an object or matter".
Q: What is that four legged object in the corner?
A: A chair.
'How' is a way to ask about the manner or way something is done.
Q: How did he die?
A: He fell off a chair.
There is an archaic sense in which, yes, you can use 'how' to mean what, but unless you are Shakespeare, I don't think you should use it.
How art thou called?
Not strictly relevant, but there are also dialect uses of 'how' that differ from the standard, but they still don't mean 'what'.
If you said the following in Inverness, Scotland:
How is Hamish at the Market Bar tonight?
You'd be asking 'why' Hamish is at the bar, not about the manner by which he arrived there.