>but because the world is ambiguous and language reflects that.
This doesn't seem like a very satisfying explanation. Take one particular example of a structurally ambiguous sentence of English:
"The company couldn't make the car fast enough".
The two meanings are completely distinct (speed of production vs. speed of the car). There's no fuzziness about this distinction out there in the world. The speed at which a car travels and the speed at which it's made are two completely distinct properties.
That is an interesting example because it looks like semantic ambiguity rather than syntactic ambiguity. But actually it is about structure as you commented -- something like this:
Regarding the meat of your comment, it is quite difficult to banish all ambiguity from natural language for a variety of reasons, but we don't really need to: humans are incredibly good at handling linguistic ambiguity. There has been a lot of fascinating research on the topic: in particular, I recommend reading up about anaphora resolution[0] and garden path sentence repair[1], because the literature includes some info on what is happening in the brain, which is significantly more detailed than what exists for most other types of linguistic ambiguity.
All of this ambiguity in natural language is something that continues to be huge hurdle for NLP: it turns out that fetching the right information from the context to resolve all the ambiguities that arise in a single conversation is completely non-trivial, despite how easy humans make it look!
An interesting case study in the opposite direction (ie attempting to remove ambiguities from natural language) is Ithkuil[2]: it is a conlang that attempted to completely banish (semantic and lexical) ambiguity and it ended up being ridiculously hard to use or learn at all.
If anyone is curious, you can plug those trees into here (http://mshang.ca/syntree/) and it will draw them for you. But my tree drawing skills are very rusty, so they are pretty basic/bad.
I'm confused about your sentence parse notation. Isn't "fast" an adjective in one of the interpretations (namely the one parsed the same as "The company couldn't make the car safe enough")?
Doesn't that "safe" example point out something else? The example with "fast" is only ambiguous because it's common to use "fast" as both an adjective and an adverb? The sentence with "safe" doesn't sound to me like an acceptable way to say that the company's manufacturing process was too dangerous.
For the alternative meaning, I think you'd say, "The company couldn't make the car safely enough." So yeah, adjective and adverb, I think you're right. For that matter, "The company couldn't make the car quickly enough" would resolve the ambiguity in one direction, but I guess not the other.
It's true that there might also be a lexical ambiguity here, but the two interpretations do also correspond to different syntactic structures. The adjectival phrase attaches to an NP whereas the adverbial phrase attaches to the VP (or thereabouts).
And yet, in the real world, people could use that sentence as part of a discussion without causing any confusion or ambiguity. Because sentences don’t exist on their own, they have a wider context which can focus their meaning.
Human language is succinct. We don’t generally say twenty words when ten would do. If the context made your example sentence clear, why would a speaker need to add any words to clarify it further?
This doesn't seem like a very satisfying explanation. Take one particular example of a structurally ambiguous sentence of English:
"The company couldn't make the car fast enough".
The two meanings are completely distinct (speed of production vs. speed of the car). There's no fuzziness about this distinction out there in the world. The speed at which a car travels and the speed at which it's made are two completely distinct properties.