John: There are many students from different countries in our school.
Su Chol: What language do you speak to each other?
John: We all speak English.
Yong Sil: Do you speak English at home, Salma?
Salma: No, I don't. I speak my mother tongue, Swahili. Are there any Korean high schools in Tokyo?
Su Chol: Yes, there's one. There's a Korean university, too...
Salma: By the way, when did Koreans come to Japan?
Yong Sil: Our great-grandparents came over to Japan before 1945. Then Korea was under Japanese rule....
(He makes no comment, and neither do I, on the extreme implausibility of the wording in this invented dialogue. Can you imagine live human beings talking like this to one another? Nor can I.)
Tami asks about nucleus placement in the second line. He thinks, rightly, that the nucleus should go on language.
What language do you speak to each other?
Yet if we apply the rule of thumb that the nucleus goes on the last new lexical item, we would expect it to go on speak.
(?) What language do you speak to each other?
Tami defends his view by saying that there is a hierarchy of accentability among lexical words, in which nouns rank first because of their richer semantic value.
I’m not sure that I would know how to measure so nebulous a quality as ‘semantic value’, but Tami is certainly right that nouns tend to be preferred over other parts of speech when we assign the nucleus. I touch on this point in my English Intonation book, §3.29.
…a more general tendency: we put the nucleus on a noun where possible, in preference to other word classes.You can contrast the Which/what/whose N type with the case where there is no overt noun, so that the nucleus defaults to the verb:
This is seen in various constructions which involve having a verb at the end of a sentence or clause. A final verb is usually deaccented, and the nucleus goes on a preceding noun.ˈHow’s the ˈhomework going?…
I’ve ˈstill got an ˈessay to write.
ˈWhich ˈbook did you choose?
ˈWhich did you ˈchoose?Compare
ˈWhat ˈbooks are you reading?with
ˈWhat are you ˈreading?
Going back to the example from the dialogue, we would have
ˈWhat ˈlanguage do you speak?but
ˈWhat do you ˈspeak?