Productions:	&alpha&beta
	&alpha&isin V	&beta &isin V	|&alpha| &le |&beta|

The strings around the N on the left-hand side of the production are the context, so a production works only in a particular context and is therefore context sensitive.

• Context sensitivity seems applicable for some aspects of natural language, e.g., subject-verb agreement.

  	John likes Mary.
  	John like Mary.

• No effective parsing algorithm is known.

• Parsing is NP-complete, i.e., would take exponential time.

• Context sensitive languages are less often used in practice than context free languages.