Oh, so you're just questioning the number of verbs in other languages that correspond to the copula in English?
More or less, yes. Or, to rephrase that: why there aren't languages that translate English 'be' with more nuance.
By most formal representations, that's how all predication works, though: "I eat cookies" is true iff "I" am in the set of things that "eat cookies". The issue is not as simple as equating things or locating things in sets. By any coherent account, a copula is something much more specific.
There's a a major difference: "eat" determines a set itself (eating things), while "be" does not ("being things"?). "Be" is without any real lexical meaning, just a grammatical function. "Eat" has real semantic content. "Eat" describes an action or a situation. "Be" does not. "Be very" does not either-- it just modifies some existing set to pick a subset of whatever that set may be.
If you're just looking for words that mean be+qualification, we do this all the time in English:
This apple exudes red.
John seems humble.
Tim passes muster as a teacher.
That haunted house exemplifies scary.
Ok, these are relevant examples. And I think we should try to determine where, if anywhere, a line should be drawn.
To me, "exudes" and "passes muster as" seem too infrequent to be grammaticalized as paradigmatically related to the copula. They seem stylistic and probably have semantic content, though it's abstract (in contrast to "eat" etc.).
"Seem", however, is a great example: I don't feel like this word has any particular lexical meaning-- rather, it is probably a modal copula, describing epistemic possibility (modality) plus 'be'. I would draw a distinction between "seems to be X" and "seems X", where the former is just a modifier and the latter is actually taking the place of the copula, assuming we don't see that as some sort of transparent ellipsis.
"Exemplifies" is intriguing-- it seems like as good a candidate as any for a set theoretic semantic representation, though in those terms it seems like just an equivalent to 'be', rather than in complementary distribution with it. I think there are two readings, one that is just 'be' in a longer word, and another where it means something like 'is the best example of', which would be along the lines of what I'm thinking, but I don't know that it's so established in English to really be considered grammaticalized in that sense. You wouldn't find translators often using "exemplifies" rather than "be", but you would probably find translators often using "seem" rather than "be" if translating from a language with markers of evidentiality.
Most of these would rarely translate back into English as "be", but that's largely because the word be is for all intents and purposes *defined* by its lack of more specific semantics.
As I said, I see a distinction between "be" and "eat", where the latter has true lexical meaning and the former serves a grammatical function, looking for a set in its argument. Likewise "be very" or "seem" would still take the core meaning from their arguments rather than the lexical entry. Compare:
*The things that be. [existential reading excluded]
*The things that are very.
*The things that seem.
The things that eat.
Or:
*Be-ers, *Very be-ers / *Extreme be-ers.
*Seemers
Eaters
So while "be" can take an argument it is not a transitive verb. That is because its argument is the only semantic content. This is still true for "seem" even though it has some (modificational) semantic content. But compare:
Exuders / Exuding things
Those that pass muster.
Exemplifiers / Exemplars
So we're left with [at least] three verbs in English that appear special in some way: be, seem, become
(*Those that become, *becomers)
The only problem with this is that 'seem' (but not 'become'?) can't take all of the kinds of arguments that 'be' does, so it can't be in a true paradigmatic relationship:
He seems happy.
??He seems inside.
*He seems (a) teacher. (?He seems a good man.)
While specific grammatical form isn't proof of anything, one further test is checking what case these verbs require for their arguments, at least on average cross-linguistically. 'be' often takes nominative, while most verbs take accusative. I think that in general verbs like 'become' and 'seem' would also take nominative arguments.
I've done a little research on the 'null copula' in Arabic (just in the present tense). One obvious question is whether it's just not pronounced. Regardless of the analysis you end up with, there is an intriguing property of the Arabic copula: when it is produced (for example, in the past tense), it takes accusative arguments:
He was teacher.ACC 'He was a teacher'
*He was teacher.NOM
This is in contrast to present tense with:
He teacher.NOM 'He is a teacher.'
*He teacher.ACC
This leads to an analysis where we don't consider the present tense to be an instance of a phonologically missing form of 'kaana' (glossed "to be" in dictionaries, etc.), as used in the past tense. Instead, it seems that 'kaana' may not even be a copula, just a lexical verb that establishes tense. Perhaps something like "It was the case that" or some meaning that can't be translated into English.
As for exactly where to draw the line between "copula" or "copula like verb" and "regular verbs" I still don't know. But "seem" is a good example, I think.
The open question: do we find any languages with a clear verb that is used when the speaker wants to emphasize how extremely a property applies to the subject? Is there a language with 'to be very' as a single lexical predicate that is in complementary distribution to 'to be'?