First, the Dothraki inflections usually and the negative grade especially are sort of weak and "unreserved".
You might say Dothraki words like to go with the flow of the sentence and the meaning it tries to deliver, but often don't dependably mark the extra stuff. You might notice that negative grade is lost here and there. If the verb stem ends in a consonant, the /-i/ suffixes don't mark the negative grade, if the verb stem ends in
o, only a few of the conjugations mark the negative grade - and funny enough, some that would lose the explicit negative grade with consonant ending, keep it with
o vowel ending:
Anha emak. - "I smile." ->
Anha vos emok. - "I don't smile."
explicit negative grade
Anha hajok. - "I grow strong." ->
Anha vos hajok. - "I don't grow strong"
no explicit negative grade
Yer emi. - "You smile." ->
Yer vos emi. - "You don't smile."
no explicit negative grade
Yer hajoe. - "You grow strong." ->
Yer vos hajoo. - "You don't grow strong"
explicit negative grade
That's the "weakness" of negative grade: it's not important enough to be dependably explicit. Then there's the "unreservedness". Dothraki has practically no rules that would restrict some vowel or consonant just to a specific use - not with affixes, and definitely not with how stems start or end. We know a couple of verbs that almost certainly just happen to have
o-ending stem:
oqolat and
holat [of the latter we don't seem to know the stem, but I'm fairly convinced it's
ho-
lat] both sound like they might come from an onomatopoetic origin. Even crazier than that, Dothraki has an extremely common and productive derivational pattern for verbs that has no connotation to negative: /-(s)o/ is a multifunctional derivational verb suffix that usually is used to center the focus on the start of an action and, if used with statives, to simply make a verb to be about state change. As this is a derivational pattern, in some cases there might be a shift in meaning and in some cases the derivation is not established, but it's pretty much guaranteed that if it makes sense easily, it's legit.
So we have:
hajat - "to be strong" ->
hajolat "to grow/become strong";
nesat - "to know" ->
nesolat - "to learn";
thirat - "to live" ->
thirolat - "to survive" etc. Not only is the negative grade lost in some declensions, it's often identical to the positive grade of a word so closely related that we might waive the difference in translating to English. For example
emat, "to smile" is by it's core meaning stative: "to have a smile" or "to be smiling". If you want to emphasize that someone began to smile, that their "face lit up", you might use
emolat (a word which we have not met but is almost certainly legit). But both
Anha em. and
Anha emo. would probably be usually best translated as "I smiled."
Knowing all this you'd think that there's no way Dothraki would allow dropping
vos. Negative grade looks the kind of verb agreement that needs the
vos to agree on, and it sounds like dropping
vos would be hard to become established as it can't be used systematically. It sounds like the derivational suffix /-o/ would bring an unsurmountable crap ton of bizarre ambiguities (if
vos could be dropped,
Anha emo could mean either "I smiled" or "I didn't smile"). Dothraki uses a lot of word-heavy redundant expressions and isn't even generally dropping-type language - it does not drop pronouns even when verb conjugation makes them redundant.
You guessed it: it's a normal grammatical thing in Dothraki to drop
vos/
vo entirely, if the verb exhibits an explicit negative grade and there's no real risk of a mixup with /-o/ ending positive-grade verbs. That's the kind of nasty unexpected pattern you mother warned you about.
Dothraki also do indeed use double negation as an emphasized negation. They may also move
vos to after the verb for a slight emphasis, and use
vosecchi (always after the verb) for a big emphasis. And of course
vos is usually elided to
vo if the following word starts with a consonant, so using full
vos when not needed is also a slight emphasis. So we have a stupendous collection of more or less emphasized negations:
Anha nesok. - "Dunno." (should not really work because
nesolat is a well established word, but I think might pass in a right context)
Anha vo nesok. - "I don't know."
Anha vos nesok. - "I do not know."
Anha nesok vos. - "I do
not know" (maybe "I know not." would be a good translation? - I think this is fairly unusual)
Anha nesok vosecchi. - "I have no idea."
Anha vos nesok vosecchi. - "I have absolutely no idea."
How far does this go? I think pretty far, as far as in colloquial English at least. So
vos avvos would be "never ever" the same as the English "not never" often is. My intuition would say it would not go as far as to the negatives of adjectives (or to the verb forms of those adjectives, because true adjectives IMO probably don't really take
vos any more than English adjectives modifying nouns take
no/
not).
In one sense the negatives are part of adjectives' negative comparison system. I'd find it odd, if Dothraki version of the syntax "He was not less handsome." would mean "He was so much less handsome," and if that works the same as in English, I'd also expect the syntax "He was not unhandsome." (or perhaps "He was not lacking in handsomeness.") to parse in the standard English fashion. These English versions are however circumlocutions, and not terribly necessary. Even if Dothraki can't really say "He was not less handsome." as easy as English, because the emphatic double negative would apply, that would not be a big loss.
In another sense, often the negatives of adjectives feel a lot like semi-independent words derived from the original. We have eg.
ojil - " incorrect," "wrong". Now, clearly this is nothing more than a negative of
jil, and should probably be inflected appropriately, so "more wrong" AFAIK would be
ojilan not *
asojilan (I've never really thought about this - needs to be addressed on the wiki). So would
Me vos ojilo. be "It's not wrong." or "It's
so wrong"? I'd kinda think the
not of
ojil is so deep in the word that it would be treated just a word, much like the engligh /un-/ words are.
... I don't have no idea about the adjectives. Could go either way.
Vos does indeed work with non-copula sentences, so
Anha vos lajak. - "I am not a fighter." is absolutely correct, and also generally modifying nouns works fine, as evidenced in Rakharo's line from season 1:
Vo mawizzi vekho jinne. - "There are no rabbits."
Your line
Me oge vos oqet oskikh. should IMO translate to "He slaughtered no sheep yesterday."
Vos works as an interjection too, AFAIK, so "Vos." is a normal response and "Voooooos!" is a normal exclamation