Pica, T.  (1994).  Questions from the language classroom:  Research perspectives.  TESOL Quarterly, 28.  pp.49-79.

1. In what ways does knowing one language help or hinder the learning of a second?
 

• Early theorists, notably Lado (1957) assumed that the more differences between one's native language and a foreign language, the more difficult it would be to learn.

 
• More recent research has indicated that the situation is not so simple:  Zobl (1980) looked at negation and articles and found that for English, Spanish speakers had more difficulty than Japanese speakers in learning negation, but that articles were almost universally difficult for EFL/ESL learners.

 
• One of the phenomena at work seems to be that limited familiarity is a trap, while extreme difference is easily highlighted and overcome.

 
• A variety of sociolinguistic factors (ethnicity, gender, L1 background, among others) affect a conversation between two speakers.

 
• Acquisition of literacy is influenced by the tradition of literacy in L1.

 
• The interactions between teacher and learner, as well as interactions between learners should not be forgotten.

 

 
 
 

References
Lado, R.  (1957).  Linguistics across cultures:  Applied linguistics for language teachers.  Ann Arbor:  The University of Michigan Press.

Zobl, H.  (1980).  The formal and developmental selectivity of L1 influence on L2 acquisition.  Language Learning, 30(1), 43-57.

Additional resources
MacWhinney, B.  (1995).  Language-Specific Prediction in Foreign Language Learning. Language Testing v12 n3, p292-320. (draft copy available in PDF at Brian MacWhinney’s website)