greeting

I am M.A student in AL-Qadissiya university My study is"investigating the difficulties faced by EFL Iraqi learners in using conversion"zero derivation" please help in answering my question: what are the sources of errors in using conversion by arabic learners,e.g, they don't know how to discriminate between adjectives and verbs in a sentence like 'he dirtied his clothes'

[Tdol]

In the example 'he dirtied his clothes', I presume youmean that some will associate the verb with the adjective 'dirty' and not see that it is a verb. Am I right? I haven't taught many Arabic speakers, so I'm not aware of the issue. What is the underlying problem in your opinion? In Arabic, can word change grammatical category easily?