Onset age for translation ability

[Mark Mitchell]

I have been assuming that young bilinguals or young children learning second
languages do not 'translate' in productive speech, at least not beyond single
lexical items (or single unanalyzed phrases learned as a whole).  In contrast,
young adolescents (around the onset of puberty) seem to have difficulties NOT
translating when learning a second language.  Thus, translations becomes the
preferred strategy.  So there would appear to be a tremendous flip-flop
occurring within this domain (which presumably parallels the onset of analysis
abilities in other domains, including nonlinguistic, as well?)  Is this notion
uncontroversial?  If so, at what age does direct translation generally become
possible?

I would greatly appreciate any references to studies which assessed the onset
of direct translation ability as well as (the empirically far more difficult
to assess, presumably) the shift to translation as a preferred strategy second
language tasks.

Best to all,
mark mitchell