How old is Chinese grammar?
As a modern Chinese word, the age of &quot;语法&quot; is about 100 years. Because modern Chinese originated from the May 4th Movement, which took place on May 4, 1919. But there was also the word &quot;语法&quot; in ancient Chinese, for example:
Case1：
《左传·昭公二十年》：“尔其勉之！相从为愈” 。 
唐-孔颖达疏：“服虔云：‘相从愈於共死。’则服意‘相从’使员从其言也。语法，两人交互乃得称‘相’，独使员从己，语不得为相从也。”。
Case2：
金-王若虚《论语辨惑二》：“故凡解经，其论虽高，而於文势语法不顺者，亦未可遽从，况未高乎！”

It can be seen that the word &quot;语法&quot; was used in the Tang Dynasty，about 1200 years ago.  In ancient Chinese, there are two words: &quot;语脉&quot; and &quot;文理&quot;，they are similar in meaning to the word &quot;语法&quot; in modern Chinese．Here are some examples:
1.&quot;语脉＂
Case1：宋-朱弁 《曲洧旧闻》卷三：“ 王临川 语脉与 南丰 绝不相类。” 
Case2：明-胡应麟 《少室山房笔丛·丹铅新录六·笨字义》：“凡读古人文字，务须平心易气，熟察上下语脉，得其立言本意乃可。” 
Case3：清-张尔岐 《蒿庵闲话》卷一：“今详语脉，首句自为一事，重在无出乡。”
2.&quot;文理&quot;
Case1：《三国志·吴志·张严程阚薛传论》：“ 张紘文理意正，为世令器， 孙策 待之亚於 张昭 ，诚有以也。”
Case2： 宋-司马光《进通志表》：“文理迂疏，无足观采。”
Case3： 明-谢谠《四喜记·双桂联芳》：“圣旨到来，宋祁文理精通，第一甲进士。”
Case4：《红楼梦》第二三回：“单把那文理雅道些的，拣了几套进去。”
Case5：鲁迅《伪自由书·不通两种》：“文理总未免有点希奇。” 

Whether it is &quot;语法&quot; or &quot;语脉&quot; or &quot;文理&quot; in ancient Chinese; Neither of them is quite equivalent to &quot;语法(grammar)＂ in modern Chinese.  Because there is no such thing as grammar in Chinese, it is only the comparison of modern Chinese people that gives rise to this concept．The grammar of ancient Chinese is mainly reflected in the use of vocabulary and sentence structure.The most prominent feature of standard Chinese grammar is that there is no morphological change in strict meaning. Nouns have no case, also have no part of speech and singular or plural．Verbs are not personal and have no tense. This characteristic, which is different from that of European languages, makes Chinese regarded by many linguists as having neither grammar nor part of speech for a long period of time in history.
《马氏文通》is the first systematic work on Chinese grammar in China. Its author is Ma Jiantong(马建通).Written in 1898, this work officially initiated the study of Chinese grammar.Taking ancient Chinese as the object of study, the book drew on the theories of Western grammar studies (mainly Latin), as well as some Chinese sayings on function characters, and established the first complete Chinese grammar system．Therefore, the real Chinese grammar can be said to have originated in 1898, at the age of 131.