Objective To investigate the relation between different extents of cleft malformation with the speech characteristics in patients with cleft palate. Methods The formant frequency of vowel [i] of 46 incomplete cleft palate patients（ICCP group） and 56 complete cleft palate patients（CCP group） before and after cleft palate repair, as well as 30 normal people（C group）, were measured and analyzed on spectrogram. Results The comparison of F1 between C group and CCP, ICCP before surgery showed no difference. So did the comparison of F1 between C group and CCP, ICCP after surgery. The comparison of F2 between C group and CCP, ICCP before surgery showed significant difference. The value of the C group was the highest. The value of the ICCP was higher than that of CCP. So did the comparison of F2 between C group and CCP, ICCP after surgery. The comparison of F3 between C group and CCP, ICCP（including before and after surgery）was similar to the results of F2 between the three groups. The comparison of F1 between before and after surgery in ICCP group showed no difference. However, the same kind of comparison of F2 and F3 showed significant differences: Both the values after surgery were higher than those before surgery. The comparison of F1, F2 and F3 between before and after surgery in CCP group was similar to that in ICCP group. Conclusion The extent of the cleft malformation is closely related to the status of the speech in patients with cleft palate. With the malformation more severe, the tongue will move backward more obviously, the elevation of the soft palate after cleft palate repair will be less active. Two ways are recommended for those patients with CCP: ①Early interceptive orthodontic treatment to reduce the extent of palate malformation; ②The hard palate repair can be performed prior to the soft palate repair. Patients with severe cleft lip and palate can have hard palate repaired while accepting the early cleft lip repair.
