Intro

Ambiguity in Language

Unusual grammatical constructions with unexpected meaning can be used to (deliberately) mislead a human reader. These are called garden path sentences. Consider some of the best-known examples:

• Fat people eat accumulates.
• The horse raced past the barn fell.
• The government plans to raise taxes were defeated.

But everyday sentences actually contain countless ambiguities which humans resolve so naturally that they do not even notice them. Knowledge of the world and context are essential.

The plant is next to the bank.

• plant
  • factory?
  • flower?
• bank
  • financial institution?
  • river side?

Types of MT Systems

Approaches to MT can be categorized by whether they work directly with surface words or whether they utilize some (linguistic) abstraction. The famous Vauqouis triangle nicely shows the possible scenarios:

Many successful MT systems disregard any linguistic information and treat all words as unrelated, indivisible units -- these correspond to the direct translation arrow.

Other systems perform linguistic analysis on the source side and then do transfer -- either to some abstract representation or directly to target-side surface words. In the first case, target-side generation is needed to create the surface words of the translation.