Introduction to Arabic Natural Language Processing.

120 Pages·2005·1.14 MB·English

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2 University of Michigan - Ann Arbor
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S June 25, 2005
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Introduction to Arabic
Natural Language Processing
Nizar Habash
Columbia University
Center for Computational Learning Systems
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• Focus of this tutorial
– Phenomena
– Concepts
– Approaches & Resources
• What is ‘Arabic’?
– Arabic Script
– Arabic Language
• Modern Standard
Arabic (MSA)
• Arabic Dialects
2
Road Map
• Introduction
• Orthography
• Morphology
• Syntax
• Machine Translation Issues
• Dialects
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Road Map
• Introduction
• Orthography
– Arabic Script
– MSA Phonology and Spelling
– Recognizing Arabic vs. Persian/Urdu/Pashto/Kurdish/Sindhi/…
– Encoding Issues
• Morphology
• Syntax
• Machine Translation Issues
• Dialects
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Arabic Script
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Arabic Script
Arabic script is an alphabet with allographic variants,
optional zero-width diacritics and common ligatures.
ﻲ ﺑِﺮ ﻌ ﻟﺍ ﻂﹸ ﳋﹶ ﺍ

Arabic script is used to write many languages: Arabic,
Persian, Kurdish, Urdu, Pashto, etc.
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Arabic Script
Alphabet
• letter forms
• letter marks
• Arabic only
• Other languages
• Persian, Kurdish,
Urdu, Pashto, etc.
OCR output ambiguity 7
•
Arabic Script
Alphabet (MSA)
• letters (form+mark)
ش س ث ت ب
• Distinctive
ʃ
/ / /s/ /θ/ /t/ /b/
ؤ ئ
ء M إ أ ا
• Non-distinctive
/ʔ/
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glottal stop aka hamza
Arabic Script
Letter Shapes
• No distinction between print and handwriting
• No capitalization
• Right-to-left
Stand
ن ب ك م ش غ
• Ambiguous
alone
shapes ز د ا
• Connective (cid:9) (cid:25) آ (cid:23) (cid:22) (cid:21)
initial
letters
• Disconnective
(cid:8) (cid:20) (cid:19) (cid:18) (cid:17) (cid:16)
medial
letters
(cid:5) (cid:1) (cid:3)
(cid:7) (cid:15) (cid:14) (cid:13) (cid:12) (cid:11)
final
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Arabic Script
Letter shaping
(cid:1)
(cid:15)&آ = (cid:15)&آ ب ت ك
/katab/ b t k
to write
(cid:1)
ب(cid:3)&آ = ب(cid:3)&آ ب ا ت ك
/kitāb/ b ā t k
book
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