语音发展迟缓(Speech delay)，是指儿童在学习发音的发展比正常同龄的儿童缓慢。语音发展迟缓，和语言发展迟缓不同，是专指发音上的困难，难以辨认某些声音，和难以运用各器官（肺部、声带、口腔、牙齿、舌头、嘴唇）合作去发出正确的字词。由于发音和语言的发展是两个不同的阶段，因此有语音发展困难的儿童可能会尝试组成句子，但别人却无法理解他所说的字词。而有语言障碍的儿童，则可能因为无法辨认或理解字词而发出一些别人不懂的声音。

Speech delay, also known as alalia, refers to a delay in the development or use of the mechanisms that produce speech. Speech, as distinct from language, refers to the actual process of making sounds, using such organs and structures as the lungs, vocal cords, mouth, tongue, teeth, etc. Language delay refers to a delay in the development or use of the knowledge of language.