FYI: This is plural "you" (or "you all").
The link goes to the full conjugation of this deponent verb. You can see it's a lot different from most of the verbs encountered early in this course.
Deponent verbs are active in meaning and passive in form.
FYI: I have no idea why there are multiple versions of the 2nd singular form. I searched, but I don't have all night. :) ... Someone else can fill in that blank, or we'll learn it later.
1st - lŏquor
2nd - lŏquĕris, lŏquis, lŏquĕre
3rd - lŏquĭtur
1st - lŏquĭmur
2nd - lŏquimĭni
3rd - lŏquuntur
More on deponent verbs:
Coordinate sentences like that are easy; you just use a conjunction. Malē loquimini et malē loquar dē vōbīs.
For subordinate sentences like "I think that you speak poorly" or "I hope that you do not speak poorly" you might need to use other constructions, like accusative with infinitive or ne + subjunctive, but these are better taught in future skills than trying to cram them all into a comment.
The verb has a passive but no active form. In formal terms, it's a "deponent" verb i.e. it "puts down" (sets aside) its active part. That's about all that we can say. Perhaps the ancient Romans would have found it strange that we think of speaking as active when they (perhaps) thought of it as passive. Maybe they felt that speech was something that happened to them. It's not such a strange idea: we fell into one rut and they fell into another.
I don't think so. The "all" is there (rather confusingly, to my mind) simply to indicate that the plural "you" is meant. In fact, I just translated it as "You speak badly", and that was accepted as correct. "All of you speak poorly" would require that there was a word in the Latin to mean "all", which there isn't.
If I understand correctly, loqui does not translate directly to "speak", and doesn't have an exact equivalent in English. If we did have an exact equivalent say "loquify" :), then you would say "it loquifies me" to mean "I speak". Similar actual constructions in English could be for example "A thought strikes me". This doesn't imply that I am not actively thinking, it just makes the thought process rather than the thinker grammatically the actor in the sentence.
I should probably carry the analogy further to say that, if we did have a "loquify" that parallels the Latin verb, then the usage "It loquifies me" would also have fallen into disuse, and the only accepted way to use it would be in the passive form "I am loquified"="I speak".
We actually do have an example of such a "deponent verb" in English in "aghast" as in "I am aghast". In Chaucer's time you could say something like "It agasses me" to mean the same thing. But now the verb survives only in the passive form "I am aghast" [*]
The actual Latin loqui is of course influential in English: e.g., loquacious, eloquent, etc.
Footnote [*] The dictionary now labels "aghast" as an adjective rather than a past participle of a verb but it doesn't work quite like an adjective: You can't say "the aghast person" the way you would use a typical adjective like say loquacious -> the loquacious person.
You're searching for logic in language. In different situations it may or may not seem "logical". Some languages say "I like the flower". Others say "The flower pleases me". Is there a great difference in meaning? If not, then why are the subject and object reversed?
"Active" and "passive" are just terms used by academics when they pull a language apart, looking for patterns. You'll never speak a language If you get caught up on looking for its logic.
La langue a ses raisons que la raison ne connaît pas