“reduction-stable entities”. To illustrate, when speech becomes fast, phones often change, but syllables remain the same. Also, syllables are related to intonational contour. There are other ways to build subwords - morphologically-based in morphology-rich languages or phonetically-based. Subwords are often used in open vocabulary speech recognition. Sub words form words. Words are important in speech recognition because they restrict combinations of phones significantly. If there are 40 phones and an average