I started to learn English since two years ago.问问大家这句话有语法错误吗

可能因为start不是延续性动词吧,感觉这里不能用have started,这是个瞬间的动作,没有持续性.
这里明显是说我两年前就开始学英语了,强调两年前开始.
since常用于现在完成时或过去完成时,不适合用在这里.可以把since 去掉
可能是对的,口语不要死抠语法书,语法只是辅助我们学习,帮助我们更好的认识英语.就像汉语一样,语法用处不大,语言就是要能清晰的表达意思就行.
since的用法：译作“自从…以来”
(1)接时间点：如 I have stayed in that country since 1995. 要求：谓v.用现在完成时,而且须是延续性动词.
(2)接一段时间 + ago：如 They have lived in that house since two years ago. 要求：谓v.用现在完成时,而且须是延续性动词.
(3)接时间状语从句：如 I have loved her since I met her last time. / Lily has stayed at home since she left school. 要求：主句的谓v.用现在完成时,而且须是延续性动词；从句的谓v.用一般过去时,而且须是终止性动词.
(4)用于句型“It’s / It has been + 一段时间 + since + 时间状语从句”中,译作“自从…以来, 已经…(时间)了”.如 It’s / has been three months since he moved to this city. 要求：主句的谓v.用一般现在时或现在完成时；从句的谓v.用一般过去时,而且须是终止性动词.
(5)用于句型“一段时间 + has passed since + 时间状语从句”中,译作“自从…以来, …
(时间)已经过去了”.如上个例句还可写成：Three months has passed since he moved to this city. 要求：主句的谓v.用现在完成时,而且动词必须是has passed；从句的谓v.用一般过去时,而且须是终止性动词.
(6)注：当since用于否定句时,主句的谓v.可以是终止性动词.如 He hasn’t seen the film since last month.
(7)相关词组：“从那时起”：ever since、since then、from then on.
注：ever since作为一个词组,放句尾可单独使用.如I have given up smoking ever since. 另外,还可在since后接句子.since前加ever,只是加重语气而已.如 I have given up smoking ever since I caught a bad cough.
(8) since还可引导原因状语从句,译作“由于；因为”,相当于because.如 Since he was lazy, he didn’t finish his homework.