Harvard-NGSL Sentences for English Learner Speech Corpora

This paper introduces a set of phonemically balanced materials for English learner speech corpora named the Harvard-NGSL sentences. They are a subset of the IEEE Harvard sentences, a collection of 720 phonemically balanced short sample phrases. Of these, 50 sentences that comprise core high-frequency vocabulary words for second language English learners were selected based on the New General Service List (NGSL). The resultant Harvard-NGSL sentences are thus learner-oriented, unlike most other phonemically balanced materials which contain low-frequency and low-familiarity words that are of limited use for learners. An analysis based on the CMU Pronouncing Dictionary found that the sentences show a similar frequency distribution of all phonemes to that of the original Harvard sentences except/3/, which is extremely uncommon in English and thus of minimal importance to learners. The advantages of the proposed materials and directions for future research are discussed.