In line with the recent bent in comparative assay of different populations (cfr. e.g. Friedmann & Rusou, 2015), Pierce, Genesee, Delcenserie, and Morgan (2017) propose a comprehensive review of different language outcomes in populations that have received qualitatively and quantitatively different input during the first year of life, from enriched stimuli in bilingual situations to no stimuli at all in the case of children with profound hearing impairment. The claims derived from these data deserve some comment, however, and need some caveats about the measures employed, which this paper will supply in the following with a brief debate of complementing inquiry and the presentation of some novel data derived from the Bilingual Language Development (BiLaD) Project, a recent French/German collaboration studying bilingual populations with and without specific language impairment (SLI).