Casual speech processes, such as /t/-reduction, makeword recognition harder. Additionally,
word recognition is also harder in a second language (L2). Combining these challenges,
we investigated whether L2 learners have recourse to knowledge from their native language
(L1) when dealing with casual speech processes in their L2. In three experiments,
production and perception of /t/-reduction was investigated. An initial production experiment
showed that /t/-reduction occurred in both languages and patterned similarly in
proper nouns but differed when /t/ was a verbal inflection. Two perception experiments
compared the performance of German learners of Dutch with that of native speakers
for nouns and verbs. Mirroring the production patterns, German learners’ performance
strongly resembled that of native Dutch listeners when the reduced /t/ was part of a word
stem, but deviated where /t/ was a verbal inflection. These results suggest that a casual
speech process in a second language is problematic for learners when the process is not
known from the leaner’s native language, similar to what has been observed for phoneme
contrasts.peer-reviewe