If your language: a) covers so little that every implementer feels a need to put their own conflicting extensions on it; b) cannot be implemented consistently

If your language: a) covers so little that every implementer feels a need to put their own conflicting extensions on it; b) cannot be implemented consistently enough that one can be reasonably confident a document will probably render nearly-enough to not be described as 'broken' across engines; and c) provides a "spec" in the sense of prose describing the author's intended meaning, but not a grammar or other formalization, test suite, etc. that can be considered authoritative for certifying that a given implementation is compliant (where compliant means that engines taking the same input will produce output close-enough to not be considered "broken" when compared to each other); then your language probably sucks. Maybe it doesn't suck in the theoretical world where everything goes exactly as the language designer fantasizes, but it sucks in the actual world where people live and operate.