You have created a duplicate, but there is no knowledge or memory of the original before using the Limited Wish option, but you can verbally control it. The saying explicitly states that no telepathy or empathy is involved.
The description of the spell in relation to the use of the limited desire to convey (some of) the knowledge and memory of the one of which it is a copy, seems (to me) to mean that he does not know any of the languages known to the language until the limited desire is cast to give those memories.
How can a simulacrum that is not yet filled with memories know what you say when it does not know any of the languages of which the original is a copy?
Or should we assume that some basic language skills prior to using Limited Wish are part of the Simulacrum spell, if so in what language are the original creatures' casters or native language.
Does anyone know if there was a decision in Dragon or any of the additions?