Sidenote:
How would you know if it would be the case?
You would know because she would make errors. Kids don't stop talking because they don't know the right word. You know that irregular past tense is hard(er) for kids to learn because they say things like 'runned' and 'eated'. In some cases it might be a circumlocution rather than an error ('I'm the big one' in place of 'I'm the biggest'), but it's not hard to know what a kid is having trouble learning if you are paying attention.
I haven't noticed her making errors that obviously relate to polysemy like that of "post". But I'm not sure what such errors would look like; my best guess is that if such things are a problem their main impact is probably just extra cognitive load, hence slower learning generally.
I'm working on a conlang (constructed language) and would like some input from the Less Wrong community. One of the goals is to investigate the old Sapir-Whorf hypothesis regarding language affecting cognition. Does anyone here have any ideas regarding linguistic mechanisms that would encourage more rational thinking, apart from those that are present in the oft-discussed conlangs e-prime, loglan, and its offshoot lojban? Or perhaps mechanisms that are used in one of those conlangs, but might be buried too deeply for a person such as myself, who only has superficial knowledge about them, to have recognized? Any input is welcomed, from other conlangs to crazy ideas.