The literature on formulaic language lacks sufficient research on how L2 learners make progress in native-like formulaicity of their target language. This study analyzed the use of formulaic sequences (FSs) by 56 Chinese university English majors in their prepared monologues at the beginning and end of a three-year period and compared the student performance with that of 15 American college students. The developmental changes of FSs were measured along three dimensions: frequency, accuracy and variation. The results showed that although over three years of college study Chinese EFL learners have made progress in frequency, accuracy and variation of the FSs used in oral production, they still fall behind the native speakers in frequency and accuracy. In addition, no significant changes could be found in error types and in most- and least-frequently occurring errors concerning FS in spite of language improvement. The most challenging area for them to tackle was the use of FSs containing prepositions and articles. The findings are of great value to language teachers as to inform them of where to direct their efforts and when to enhance the idiomaticity and fluency of their students' oral production. (Contains 6 tables.)