In Afrikaans, verbs usually do not change form in the present tense the way they do in English.
So you get:
That means gee stays the same, even with die lamp as the subject.
Yes, but in this sentence it is being used in a natural extended sense.
Die lamp gee lig means that the lamp gives off, produces, or emits light. English often uses give this way too, as in This fire gives a lot of heat.
So gee still means give, but the natural English translation may sound more like The lamp gives off light.
Because lig here refers to light in general, not to one specific countable object.
Afrikaans often leaves out the article when talking about something as a general substance or concept. So lig here means light in the general sense.
If you added 'n and said 'n lig, that would usually mean a light as a lamp or light source, not light as the thing a lamp produces.
A rough guide is:
A rough English-friendly approximation would be something like:
dee lamp khee-uh likh
The exact pronunciation depends on accent, but the main thing learners notice is that the g sound in gee and lig is the typical Afrikaans guttural sound.