grammar - How do you call..? vs. What do you call...?

It seems an open-and-shut case, the correct version for asking the word of something in English is

What do you call…?

And yet the sheer number of second-language speakers of English who ask daily, the following

How do you call…?

is extraordinary and cannot be ignored easily. Romance languages such as French, Spanish, Portuguese and Italian use the adverb how in “What do you call this?”

Comment appelle-t-on cela ? (French)
¿Cómo se llama esto? (Spanish)
Como se chama isso? (Portuguese)
Come si chiama questo? (Italian)

And apparently, Russian speakers make the same mistake too. However, if the verb call is replaced with a different verb, i.e. say, the request "What do you say this?" becomes extremely unidiomatic; the determiner what must be replaced with how.

How do you say this?

That phrase has the following meaning: “In what way or manner do you say this word?”

The “how do you call...” construct is uttered even by proficient speakers of English. Would anyone have noticed the discordance in the following quotation if I hadn't emphasized that expression?

... actor was so obsessed with accurately portraying his character that he started losing sleep over it. “It’s a very – how do you call that? – sensorial condition. So I’m like, ‘I need to experience that, be in that zone when you’re constantly paranoid, where your senses work at 200 percent.’ You hear more intensely, you feel more intensely. And so, because I got so anxious I stopped sleeping, but not as a choice. And, all of a sudden, I started to have these symptoms,” he explains.

euronews.com (Mar 21, 2016)

Perhaps there is evidence to suggest that the construct “How do you call (something)” has begun entering the English lexicon, as demonstrated in a speech made in Hanover, Germany, by the current President of the USA, Barack Obama

“I truly believe you’ve shown us the leadership of steady hands,” Obama said, imitating the way she likes to hold her hands in public, with the fingers arranged in a sort of rhombus, or as the Germans call it, a Raute. “How do you call it?” Obama said with a smile. “The Merkel Raute?”

_{Time (April 26, 2016)}

UPDATE 5 June 2016

Two more examples of just how common it is to hear and read the ‘ungrammatical’ construction by both non-native and native speakers.

• Novak Djokovic confirmed he has become a vegetarian after already having adopted a gluten-free diet. "It's been almost a year. How do you call that? A pescatarian, a vegan with eating a little bit of fish here and there." _{May 27, 2016}

and

I didn’t think my leaving US Vogue would be big news. I went – how do you call it – viral. That was funny. I just thought. ‘Oh good, maybe I’ll get a job now’. _{Grace Coddington 21 May 2016}

Not that long ago, I posted the following three links that clearly explained to a user on EL&U why the constructs “How do you call ... ?” or “How would you name … ?” are ungrammatical.

1."How do we call (something) in English?"
2. What vs. How from Pearson and Longman's message board (also cited in an answer)
3. How to ask for the name of something?

The user remained unimpressed and totally unconvinced, while I asked permission to cite his words which he agreed to, I have preferred to keep him anonymous:

(2) For example, "Are you crazy about Jack?" - "How do you mean 'crazy'?'' - It would be way more logical to say that the speaker here is, in fact, inquiring the reazon why the interlocutor said "crazy", and to say that the speaker is "inquiring the way how his interlocutor means the word 'crazy'" would be quite a stretch. @_____

Interestingly, the British English corpus yielded no results for “How do you call...” but when I searched the American English corpus using Google Ngram the following graph appeared. Admittedly, the results support overwhelmingly the “What do you call..” but I never doubted that for one instance. I am however open-minded enough to ask myself "why" and "how" this slow shift has come about.

Questions

1. What evidence is there that "How do you call ..." is, or is not, a legitimate phrasal usage or expression in English?


2. Could it be called a dialectal variant? Why is it considered non-standard?


3. How do linguists define the "How do you call ..." vs. "What do you call..." debate? Has any interest been shown in this lexical divergence between Romance languages and English?