Granted we already did with this when we speak, but if you are reading words, then there is the chance to be explicit and avoid the confusion from the beginning as you can specify intent with words.
Additionally, when speaking, you (generally) have a real-time situation going on, where you can query the speaker and get them to clarify if their language is imprecise. Exceptions to this (recorded sound), significantly post-date the phonetic evolution of the English language, in the same way the written word does. And of course, you don't have the additional communication channels (inflection, tone, body language, etc) that generally accompany the spoken word.
English is pretty robust, really. Make a couple of mistakes, and you can still usually determine the meaning. But, despite what people frequently seem to think, making lots of grammatical errors does obscure your meaning, especially if you're trying to communicate technical or complex thoughts. Without knowledge of grammar, you're limited to general, simple sentences.