Computer software is commonly used to translate text from one language to another. As part of his Ph$.$D$.$

thesis, Philipp Koehn developed a phrase$-$based translation program called Pharaoh. The quality of the

translation can vary. A good translation system should match a professional human translation. It is important

to be able to quantify how good the translations produced by Pharaoh are. The IBM T$.$ J$.$ Watson Research

Center developed methods to measure the quality of a translation from one language to another. One of these is

the BiLingual Evaluation Understudy $($BLEU$).$ A BLEU score is a number ranging from $0$ to $1$ that indicates

how well a computer translation matches a professional human translation of the same text. Higher scores

indicate a better match. BLEU helps companies who develop translation software $"$to monitor the effect of

daily changes to their systems in order to weed out bad ideas from good ideas."