About translation of cultural language

Let me recapitulate. We started by emphasizing how different are "the others" -and made them not only different but remote inferior. Sentimentally, we then took the opposite track and argued that all human beings are alike, but that didn't work either, "the others" remained obstinately other. But now we have come to see that the essential problem is one of translation. The linguists have shown us that all translation is difficult, and that perfect translation is usually impossible. And yet we know that for practical purposes a tolerably satisfactory translation is always possible even when the original "text" is highly abstruse. Lenguages are different, but not so different as all that. Looked at in this way social anthropologists are engaged in establishing a methodology for the translation of cultural language. 

--Edmund Leach.

A eso, Lydia Liu responde: 

One would like to have as much faith in the power of cultural translation as Leach, but the phrase "practical purposes" lets the cat out of the bag. To me, the crucial thing here is not whether translation between cultures is possible (people do it anyway), or whether the "other" is knowable, or even wheter an abstruse "text" is decipherable, but what practical purpose or needs (which sustain one's methodological paraphernalia) bring an ethnographer to pursue cultural translation. This is precisely the point at which linguistic constituency, and in the name of what kinds of knowledge or intellectual authority does an ethnographer perform acts of translation between cultures?