In Russian, you can even construct sentences consisting of a few verbs and containing no other words, for example:
Решил пойти купить поесть. = I've decided to go to buy (some food) to eat.
The above sentence is perfectly natural.
''Let's meet to discuss this.'' How would I translate this
construction to Russian? Can I just add the infinitive like in
English?
Your translation (''Давайте встретимся поговорить об этом'') sounds slightly not natural, but even native speakers can use such a phrase. I am unsure about the formal rules in this regard - maybe there is a formal mistake in it and maybe there isn't. To stay on the safe side in terms of the formal rules and to sound fully natural, say, ''Давайте встретимся, чтобы поговорить об этом''.
There is also a commonly used colloquial expression, ''Давайте встретимся поговорим об этом,'' meaning meeting to discuss something and pronounced without any pauses between the words, but I suspect it is formally ungrammatical. If you put a comma between ''встретимся'' and ''поговорим'' (corresponding to a pause in speech), the sentence definitely becomes grammatical, but the perception changes, ''Let's meet and, in particular, discuss this.''
By the way, ''to discuss this'' is better translated to ''обсудить это,'' whereas ''поговорить об этом'' is rather ''to have a conversation about this.''
Also, does this affect the aspect of the verb (говорить/поговорить in
the above examples)? I've been taught that with modal verbs like
хотеть you usually use the perfective form of the verb.
That's a very tricky question.
On the one hand, you can say ''хотел учиться'' and ''хотел выучиться'' as well as ''захотел учиться'' and ''захотел выучиться''. All four phrases work and sound natural. The choice between them is just a question of the precise meaning.
On the other hand, some combinations in some contexts indeed sound very weird. Imagine you decide to talk with someone on a certain topic. You approach the person and say, ''Я захотел говорить с тобой по поводу Х''. This sentence is really very unnatural, in the circumstances. There is nothing ungrammatical in it, but the sentence sounds utterly weird. It would also be weird to say, ''Я решил говорить с тобой по поводу X.'' However, the negation sounds perfect, ''Я решил не говорить с тобой по поводу X.''
The weirdness comes from the precise meanings of the verbs. ''Говорить'' is usually perceived as ''to talk in general,'' as opposed to ''поговорить'' - ''to have a specific conversation.'' If you say, ''Я решил говорить с тобой по поводу X,'' it will sound like, ''I have decided to talk with you on subject X in general, not only now.'' The meaning is just weird and does not correspond to what you actually have decided. And if you say, ''Я решил не говорить с тобой по поводу X,'' it will sound perfect and will mean, ''I have decided not to talk with you on subject X in general, not only now.''
To conclude, the appropriateness of using the imperfective form after verbs like ''хотеть'' is determined by the precise meaning of the words and the intended meaning of the message.