hear it say it learn it
Can you say ليس أَعْرِف instead?
Because ليس is an imperfect verb which needs 2al-mubtada2 (subject) and 2al-khabar (its predicative adj./complement), and cannot be followed by another verb (such as أعرف) directly.
"The book is not new"
ليس الكتابُ جديداً
الكتابُ ليس جديداً
I am no expert in Arabic, but I think the answer to your question must be no, because, as far as I know, 'laisa' means 'there is not'.
You can't say ليس أعرف you should either say لا أعرف or لست أعرف because you are speaking about yourself
The sentence لسْتُ أعرف cannot be done. If we insist on connecting two verbs, we should use أن المصدرية between both. So, it is: لسْتُ أن أعرفَ
I accept any feedback. (But, definitely two verbs cannot be joined).
As far as I know لا is only used when not followed by any word, instead, we should use ما orليس