The contributions to this special issue were selected from a wealth of studies presented at the first Workshop on Infant Language Development held in Europe (Donostia, Spain) including keynote talks by such prominent infant researchers as Jenny Saffran, Marilyn Vihman, Krista Byers-Heinlin, and Dick Aslin. One of the many goals of this meeting was to bring together researchers who work on the acquisition of various languages. For this reason, research reported in this special issue includes experimental data from German, Japanese, Basque, Spanish, Italian, French, British, English, and American English infants. By investigating various abilities of infants from all these linguistic backgrounds, the articles published within this volume cover the research fields of speech perception development, cognitive development, and the development of word comprehension and production.