Would you slow the learning plan down if a learner in a non-Arabic-speaking home has improved enough that the old lesson length no longer seems to fit?

Lesson duration can be reconsidered when the learning task changes. Base the decision on what now needs to happen inside the session rather than keeping an old format simply because it is familiar. When Arabic is rarely heard at home, extra repetition of sounds and vocabulary may be needed before they feel automatic. It is usually better to fix the smallest blocking skill first than to keep adding harder material.