Like any other languages, English for one, Chinese (Mandarin) is spoken in rhythm. In the flow of speech a sentence is firstly divided into sense groups, based on both sense and constructions, as well as rhythm (今年\这里的春天\来得比去年晚一点;所以\我也想给你写信 (so I \want to\ write to you \too) ), then (rhythmic) words (it's rhythmic, not gramatical or lexical, words that work as rhythmical unit in speech flow. Rhymic words are very common in Chinese speech, though lots of which you cannot find in dictionaries( 小李伟 little Liwei, Liwei Jr. 跑走(了)), for instance, 所以\我也想\\给你写信 or 所以我\也想\\给你\\\写信 or 所以\我也\\想给你\\\写信.-------------------------------- Generally speaking, a Chinese rhythmic word consists of two, three or one syllable. Grammatical\lexical words composed of four or more syllables, such as 中华民族(G), 大不列颠及北爱尔兰联合王国(L),are cut into 2\3\1-syllable rhythmic word(s) in real speech, 中华\民族, 大\\不列颠\及\北\\爱尔兰\联合\\王国. -------------------------- Secondly, also like any other language, Chinese speech has its stressed and unstressed syllables. Actually in almost every rhythmic word each syllable has its respective different intensity/strength/loudness/dynamics, only in some words the difference is apparent and in some other words not so much obvious. ------------------------------------- So you don't have to worry about the sound change (sandhi) mode for the character/syllble group consisting of four or more syllables. What matter are the 2/3 rhythmic words.