My english is shit and I'm having no problems with this game
I only had problems with that vent at the beginning, and I don't even think you are supposed to understand that.
Also, the more I play, the more I think this decision wasn't an oversight. I think it may have been a design decision to encourage people to play more than once, because there are other incidents similar to the vent, where you hear things in the background and are "supposed" to strain to hear them. Also, in the city streets, in gameplay, subtitles really wouldn't be possible, even though there are important audio cues.
So basically, in some situations, they don't want you to catch every word, and for general gameplay, any subtitle implementation would have to be uselessly, confusingly half-assed.