Ordinary negative لَا, jussive لَمْ, subjunctive لَنْ, and prohibitive لَا are not interchangeable.
PhraseFunctionMeaning
لَا يَقُولُPresent negationHe does not say
لَمْ يَقُلْJussive, past negationHe did not say
لَنْ يَقُولَSubjunctive future negationHe will not say
لَا تَقُلْProhibition, jussiveDo not say!
Is the speaker denying a proposition or instructing a person not to act? This distinction helps identify the relevant lā.
Opening interactive controls...
Advanced Sarf Application: Ambiguous Forms, Weak-Letter Reasoning and Error Correction
Ordinary negative لَا, jussive لَمْ, subjunctive لَنْ, and prohibitive لَا are not interchangeable.
PhraseFunctionMeaning
لَا يَقُولُPresent negationHe does not say
لَمْ يَقُلْJussive, past negationHe did not say
لَنْ يَقُولَSubjunctive future negationHe will not say
لَا تَقُلْProhibition, jussiveDo not say!
Is the speaker denying a proposition or instructing a person not to act? This distinction helps identify the relevant lā.