At st6, as soon as the dinner is over, and the klingons take their places on the transporter in order to return to Qo'noS wa', cheng is heard saying:

DaH machegh

I'd rather expect to hear {DaH wIchegh}. The {DaH machegh} gives me the impression of cheng saying, "now we return somewhere unspecified on something which is unspecified too"

chegh is one of those verbs whose object is automatically given a locative sense. The object of chegh is the destination to which you are returning. If you do not include an object, the destination to which you are returning is considered to be general or vague.

Let's remember that DaH now is an adverbial, not a noun, and is not the object of this sentence. Let's remove it to avoid confusion.

wIchegh means we return to him/her/it. This is clearly not what cheng Sa' means to say: what it does he mean? On the other hand, machegh we return (to someplace unspecified) is exactly what he means: the person at the other end of his communicator knows exactly what he means, so he doesn't bother to say where they're returning to. He doesn't need to. He could say Duj wIchegh, but his transporter operator already knows that. When Kirk says beam us up, he doesn't have to say beam us up to the ship, does he? No.

Remember also that the verb imparts a locative sense to the object; the locative isn't dangling off the verb into space. If there's no object, there's no locative. chegh without an object means return.

-- 
SuStel
http://trimboli.name