Much literature exists on foreign language learning by Putonghua and Cantonese speakers, but there is relatively little on how Putonghua speakers learn Cantonese.

This study focuses on second language acquisition of Cantonese by learners whose L1 is Putonghua. We aim to investigate which aspects of pronunciation are considered the most difficult by learners, which of the errors found occur most often, and whether negative L1 influence exists in L2 acquisition and, if so, the forms such influence takes.

Some 80 questionnaires were administered and eight speaking tests were conducted. The questionnaires enabled the researcher to obtain the information about subjects' linguistic and education background, and subjective responses of their Cantonese proficiency whereas the speaking tests incorporating the reading of 24-disyllabic-word list and story-making could help to justify subjects' mastery of Cantonese.

We have the following findings: (1) Most of the interviewees mentioned tones as constituting the most difficult area. (2) High entering tones were most commonly rated as the hardest ones. (3) Most of the errors predicted in the comparative study of the phonology systems of Cantonese and Putonghua matched the actual errors produced by learners. (4) Negative L1 influence emerged in the form of interference errors and developmental errors. (5) Tone 3 engendered the highest occurrence of non-entering errors whereas Tone 8 comprised most errors among entering tones. (6) Second language acquisition of Cantonese was often under a combination of influences of L1 and L2 rather than L1 influence alone, although there are some other factors affecting the acquisition. Our findings are expected to have pedagogical implications for learners.