Modeling Focus Prosody in Hijazi Arabic: A Two-Stage Machine Learning Approach to Classification and Localization
This study investigates how prosodic focus is encoded in Hijazi Arabic using a two-stage machine-learning framework trained on an annotated corpus of scripted speech. We model the predictive contribution of acoustic-prosodic cues: F₀ excursion, intensity, duration, and pitch-level measures (mean F0/max F0/min F0), and, for region-level analyses, phonological metadata (e.g., syllable weight). Stage 1 asks whether an utterance contains focus (Focus vs. Neutral). Evaluated on a natural, imbalanced test set (≈90% Neutral: 10% Focus), a Random Forest achieved Macro-F1 = 0.580 (95% CI: 0.561–0.600) and Accuracy = 0.696 (95% CI: 0.680–0.713), with ROC–AUC = 0.879 and PR–AUC = 0.511. A threshold sweep identified τ ≈ 0.80 as a recall-oriented operating point (P ≈ 0.44, R ≈ 0.61, F1 ≈ 0.51). Feature-importance analysis shows that excursion, intensity, and duration dominate over static pitch height. Stage 2 extends the task to localizing focus regions (On-, Post-, Pre-Focus). Overall performance reaches Macro-F1 ≈ 0.65 (Accuracy ≈ 74.6%), with the Post-Focus region best detected (F1 ≈ 0.85, Recall ≈ 0.87), reflecting robust post-focus compression, while On- and Pre-Focus are weaker and more confusable. Taken together, the results place Hijazi Arabic within a range-driven, +PFC typology: focus is realized by larger F₀ excursions, increased intensity, and lengthening on the focused item, followed by systematic post-focus compression. The approach provides a replicable ML methodology for modeling focus realization in under-resourced dialects and yields findings compatible with PENTA target-dynamics and interpretable within Autosegmental-Metrical accounts.
This study investigates how prosodic focus is encoded in Hijazi Arabic using a two-stage machine-learning framework trained on an annotated corpus of scripted speech.
Experimental studies show that the prosodic realization of focus varies across Arabic dialects. This study examines focus in Bedouin Hijazi Arabic. Using the question-and-answer paradigm, eleven…
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