Two points:

1. If you look at dinlemek in the dictionary, you will find |ı| written next to the translation. This means that this verb takes an accusative object. If there was a case ending thus it would be radyoyu according to the vowel harmony rules.

2. In Turkish, only the definite object is marked with accusative. As your sentence asks if the person is listening to the radio in general the object is indefinite and unmarked.

That´s why

         Radyo dinliyor musun?

Sure. But no old discussion can offer the excitement of a new problem which you know others are trying to solve at the same time. You see, it´s a competition.

Yes, I have seen this cube before. I understand the position of the vowel in the cube represents the place of its pronouncing in the mouth. We have a vowel harmony in Finnish, too: a, o, u and ä, ö, y (ü) do not occur in the same word but e and i are free to pop up whereever they like. It´s a feature in language that serves economy.

But it can be lost, too. This is what happened in Estonian. (I guess during history they just had a few armies too much marching through their lands.)

What a nice discussion you had here while I was absent. I suggest we make this a long thread where learners can bring interesting/difficult sentences for all of us to think of.

If the comparable verb has disappeared (gone through serious phonetical changes) from the dictionary the more reason there is for -iyor- to be swallowed up. -ebil- still has some hope because speakers can recognize the independent verb that it represents.

But who knows. Turkish is quite stubborn with its vowel harmony but it also tolerates many exceptions without staggering in its principals. The massive scramble of loan words didn´t effect the phonetical rules of the language.

These changes happen very slowly. When they become reality none of us will be around to post a "what did I say" message to the forum.

Grammaticalization is a language universal. And in my opinion, -bilmek is on this path into a full suffix. It is fighting against. For instance, it refuses to follow vowel harmony. But it will have to give up.

I don´t know how to call it. I understand what you mean when you object the term auxiliary. It doesn´t take into account the special characteristics of Turkish grammar. But in every language grammatical elements tend to develop from frequently used lexical elements.

But this is how auxiliaries are born. They are ordinary verbs in the beginning and then they adapt more and more grammatical functions. In the end they lose their own special characters and begin to mainly serve the main verb. Besides, auxiliary as a linguistic term is not a yes or no question, its more like a continuum from relatively full verbs of the lexicon into transfixed grammatical elements. German or Swedish modal auxiliaries, for instance are not as grammaticalized as those of English.

I agree it was not a good idea to call them auxiliaries. Especially the English concept of auxiliary is misleading because verbs like must and can have gone so far in their grammaticalization and lost most of their conjugation in this path. If you try to look for something comparable in Turkish it has already turned into morphological endings, the forms of the old ermek maybe?

What I ment is something like a helping verb, a grammatical hanger. In this job the regularity and the full conjugation of etmek, yapmak, vermek are an advantage.

Thanks, si++. I feel like a plucked hen.

I understand what you mean, MarioninTurkey. Something is telling me in the back of my head that these are lexical questions in the end. I mean when you learn a new verb it belongs to the package to learn also how it is used and what it governs (like in every language). I guess what makes it look more difficult is that these duplexes are very usual and often basic in their meaning. (Maybe my question should be formed again: why is there two words in the place where I got used to seeing one?)