"We will speak to each other after we have eaten."
We don't have good guidance on that and we don't have any reason to believe that there are any verbs where the prefix trick cannot be used. But there are plenty of situations where the prefix trick would not be clear and could cause confusion, so care should be taken in its use.
There are probably some situations where the prefix trick would make sense with jatlh. But just to be clear, given the thread that this is in, I would like to clarify that the prefix trick may not apply to the use of the type 1 verb suffixes and that is further reason that it is probably a bad idea to use jatlh on this exercise.
Remember that verb prefixes do not enforce subjects or objects in their use; they simply agree with whatever subjects or objects are on the verb, even if those subjects or objects have been elided.
If someone says SoH qalegh jIH I see you, the subject is first person and the object is second person, not because the prefix makes them so, but because those are the arguments that the prefix is agreeing with. When you see a verb with the subject and object elided, like qalegh I see you, you're not seeing a verb where the prefix has been given the power to enforce subjects and objects; you're seeing a verb where the prefix is simply agreeing with a subject and object that have been dropped off the verb. The SoH and jIH are still the subject and object, even if they've been elided.
Now, it's important to remember that when I said object above, I mean both direct objects and indirect objects. The prefix can agree with either. Normally, the prefix agrees with the direct object, but under the conditions that Okrand spells out in the link I posted above, the prefix can agree with an elided indirect object. The prefix will never agree with an indirect object that is actually stated.
So if you see a word like qajatlh, since you know you can't speak a person, that qa- must be agreeing with an elided indirect object. It's "short" for SoHvaD jIjatlh I speak to you. But if you see qalegh, I CAN see you, so the qa- will be interpreted as agreeing with a direct object.
So under the rules given by Okrand, semantics play a key role. You have to know what kinds of objects the verb might take or not take before you can start deciding whether a verb prefix can agree with an indirect object. THAT is how you decide whether you can use the prefix trick, not by using a list of verbs that it works with.
I see what you mean now after seeing your explanation below. You mean that the person you are speaking to is not the direct object of jatlh. At least I think that is what you mean.
But does that mean you can't use -'egh or chuq with it? I mean if you can use the prefix trick to have the prefix stand in for an elided indirect object then why can't you also use -'egh or -chuq with it to mean that you speak to yourself or they speak to each other?
Nobody said you can't, but -'egh and -chuq have their own rules about prefixes and do strange things with objects. We have no idea how the prefix trick might interact with that. The only safe thing to do is to assume they are incompatible grammar and not try to use them together.