→ Main entry: Contrastive Analysis
The Contrastive Analysis Hypothesis (CAH) is the predictive claim that emerges from contrastive analysis — the systematic comparison of two languages. The hypothesis, most strongly associated with Robert Lado’s Linguistics Across Cultures (1957), holds that:
- Differences between L1 and L2 will cause difficulty and produce errors (negative transfer)
- Similarities will facilitate learning (positive transfer)
- The degree of difficulty is proportional to the degree of structural difference
The CAH exists in two versions:
- Strong version: All L2 errors can be predicted by comparing L1 and L2 structures. This was largely falsified — learners make many errors not predicted by contrastive analysis (developmental errors, overgeneralization) and avoid many predicted errors.
- Weak version: Contrastive analysis can be used to explain errors after the fact, even if it cannot predict them all in advance. This version remains influential and is widely accepted.
The strong version was challenged by error analysis and interlanguage research in the 1970s, which showed that many L2 errors are developmental (shared across learners of different L1s) rather than transfer-based. However, the weak version and the broader enterprise of contrastive analysis remain valuable tools for curriculum design and error explanation.
See the full entry at Contrastive Analysis for detailed history, methodology, and the strong/weak distinction.