Dataset: 8,045 passage pairs from UBC-NLP / NileChat Arabizi-Morocco, split into 6,436 training, 804 validation, and 805 test pairs. Its Arabizi was generated from Arabic-script Moroccan material with Command R+; performance on naturally authored Arabizi remains untested. Source data is subject to upstream access conditions and CC BY-NC 4.0.
Human audits: two native Moroccan Arabic speakers independently accepted all 300 sampled test references. All-positive labels make Cohen’s κ undefined. A separate 100-pair audit found 75 aligned and 25 misaligned positional training pairs. Review of 50 apparent LSTM errors yielded 42 true errors, 5 acceptable variants/non-errors, and 3 uncertain cases; this error-conditioned sample is not an accuracy estimate.
Interpretation: mT5 uses full passages, external pretraining, and more eligible training data than the word-level systems. This is not an architecture-controlled comparison. All 78 mT5 outputs that failed to emit EOS within the generation limit remain in the primary scores. Split provenance and source-document independence retain limitations described in the manuscript. The exploratory human mT5–MLE review does not establish a human-preference winner.