[Grammar] Question re. word order

[Mjanedoe]

As a Brit. living in Germany I am often asked by the Germans "what means ..... in English", and I want to correct them and tell them that we cannot say "what means......in English" we have to say "what does.....mean in English" , but I cannot think how to describe the grammar behind it .
"To mean" is a verb ...so why can´t we say " what means .."..I would really like to understand why in this case it has to be used with " to do ",so I can understand and can then correct my friends with a proper explanation behind it .
It´s driving me crazy, not being able to fathom it out !

Many thanks for any help
Melanie

[orangutan]

Question formation in English involves (in most cases) the rule of Subject-Auxiliary Inversion (the subject goes after the auxiliary). If there is no auxiliary involved, as in the present and past simple, the auxiliary "do" is brought in. I find it helpful to mention to students that "do" can also be used in affirmative sentences, though this usage is rather marked in modern English: for example "it does mean" is an alternative to "it means" (only different in emphasis).

In modern English, only auxiliaries (and the copula) undergo this form of inversion. (I include modals as auxiliaries.) This is in contrast to French, and also older forms of English ("where goest thou?").

Afterthought: since you are living in Germany, it is easy for Germans to confuse English interrogative word order (Subj-Aux inversion, as described) with their own rule that the finite verb must come second, which also involves the postposition of the Subject in questions, but is of course not the same rule.

[Mjanedoe]

Many many thanks Orangutan !
So relieved to have that clear in my head now and I am looking forward to be able to properly explain WHY we form the sentence like that instead of just saying " I don´t know why ..we just do "!
thanks once again for your time.

[orangutan]

Sehr gerne! :)