→ Main entry: Cross-Linguistic Influence
“Crosslinguistic influence” and “cross-linguistic influence” are the same concept — the term is spelled both with and without the hyphen in the literature. The hyphenated form (cross-linguistic influence, or CLI) was introduced by Kellerman and Sharwood Smith (1986) and is the more common academic spelling, but both forms appear in published research.
See the full entry at Cross-Linguistic Influence for a comprehensive treatment of positive transfer, negative transfer, and bidirectional influence across all known languages of the learner.