The German ARD TV published full raw video of the interview, that is with journalist asking questions in German, and Yatsenyuk replying in Ukrainian. Well, mostly Ukrainian.
Unfortunately, I am not an expert in Ukainian language, albeit have quite an experience of learning languages.
He speaks Ukrainian, yet for some reason he uses a couple of English words.
At 0:30, he says about cyber-attacks on some German official web-sites that took place just before his visit to Berlin. I just do not understand why he says 'cyber' in English manner, that is [sai-ber]; whether in Russian or Ukrainian he should say 'кибер' (кiбер for Ukrainian), that is pronounced with [ki-], like in 'kee'.
And further, when talking about this very invasion, — at 1:23 — he literally says 'invasion', pronouncing the word in English (using it grammatically as if it was feminine gender, which shows adjective 'Soviet' in the genitive fem. form, 'радянську').
As if he suddenly forgot his native Ukrainian word 'вторгнення' (by the way, grammatically it is neutral gender and would require the word 'Soviet' in the corresponding form — 'радянськo'), which is quite a strange supposition taking into account that they have been speaking about mythic Russian invasion for more than half a year.
I think the world remembers he speaks pretty fluent English by his countless interview he gave during 'maidan' to the Western media. But what does this 'invasion' in his head mean for Ukraine, Russia and Europe, I don't know. I'm afraid, nothing good.