"Koho tady potřebujeme?"

Translation: Whom do we need here?

[TTDan]

Perhaps my English grammar is poor but I would be far more likely to say 'Who here do we need?'

It seems more emphatic on the 'here'.

[Yatagann]

I would be far more likely to say "Whom do we need here?" Here feels odd in the middle of the sentence. Also your example would also use 'whom', not who, as it is the object of the verb, need.

[hajrn]

I wrote "Whom do we need in here?" Could this be right?

[BoneheadBass]

From the English side, "in" adds an element of location that is not present in the Czech sentence.
It restricts "here" to someplace indoors, while you could just as well use this question outdoors.

[Chessnecof]

Interesting, I didn't know about the accusative case in English. Očividně I'm learning two languages here.

[BrianSille2]

Yes, but it is quickly going out of fashion! Most people now would use WHO.

[AgnusOinas]

I would say it went out of fashion decades ago, then it partially came back into fashion in the recent years ("oh look, I'm sophisticated"), and now it's going out again, leaving people divided - some insist "whom" must be used for objects, some insist it's obsolete.

[svrsheque]

...with both sides dragging us into their little civil war.

[BrianSille2]

It is all part of the development of language. All languages tend to simplify with time, although sometimes they will become more complex. At my age I don't have time to wait for the simplification of Czech!

[AgnusOinas]

Any significant simpification of Czech might take centuries. None of us have that much time ;)