Is Chinese really that ambigous in oral communication?
The "Lion-Eating Poet in the Stone Den" (施氏食狮史) is an anormality or a very "perverse" case. Characters will often have the same pronunciation (see Does xiang (third tone) mean &quot;want&quot; or &quot;echo&quot;?). However, with some context, in the form of either a "term" or a phrase that the character forms, it is possible to distinguish between characters. If someone says sha1 si3, I can probably safely assume that they mean 杀死 (unless there's some other parsing of their speech that makes more sense). If someone says hua1 yuan2 zhong1, I can safely guess that they mean 花园中.

This is possible even if the tones are missing: for example, I could guess the characters for ru guo quan shi jie wo ye ke yi fang qi (i.e. 如果全世界我也可以放弃) even though I had only had heard this phrase in a song. (Singing will obscure the tones used for characters.)

Consequently, issues of ambiguity in oral communication are, to the best of my knowledge, limited to cases where context cannot be provided, such as with identifying the component characters of people's names. These can be rectified if the speaker provides example usage of each character (e.g. 元朝的元, 责任的任).