Authors: Usman Nawaz, Muhammad Junaid Iqbal, Muhammad Asaf, Mariam Munsif Mir, Faisal Rehman, Tahir Alyas, Muhammad Hasnain
Organizations: Independent Researcher, Palermo, Italy · University of Rome Tor Vergata, Rome, Italy · DIMES, University of Calabria, Rende, Italy · School of ICT, Griffith University, Nathan, QLD 4111, Australia · University of Mianwali, Mianwali, Pakistan · Department of Computer Science, Lahore Garrison University, Lahore, Pakistan · School of Computer Science, Minhaj University, Lahore, Pakistan
Part-of-speech tagging is a fundamental sequence labeling task and an important component for many downstream natural language processing applications. However, Saraiki, written from right to left in a Perso-Arabic script, remains an under-resourced Indo-Aryan language, despite being spoken as a mother tongue by 28,849,579 people (approximately 28.9 million) according to Pakistan 7th Population and Housing Census 2023. This paper presents a manually annotated Saraiki Universal POS tagging dataset developed from plain-text. We annotated the text with 17 POS categories. We evaluate three pretrained transformer encoders under the same fine-tuning setup: XLM-RoBERTa base, Urdu RoBERTa small, and multilingual DistilBERT. Experimental results over five random seeds show that XLM-RoBERTa base achieves the best performance, with 87.29% +/- 0.21% development accuracy and 88.60% +/- 0.21% test accuracy. Urdu RoBERTa small and multilingual DistilBERT also provide competitive results, suggesting that multilingual and related-script pretrained encoders are effective for Saraiki UPOS tagging. The dataset, evaluation setup, and baseline results introduced in this work provide a benchmark for future research on Saraiki NLP and low-resource sequence labeling.
Figures & tables
Dataset Split
Sentences
Tokens
Training
1,666
28,377
Development
208
3,636
Test
209
3,439
Total
2,083
35,452
Table 1: Dataset statistics for the training, development, and test splits.
Tag
Train
Dev
Test
Total
ADJ
1,430
205
153
1,788
ADP
4,235
544
526
5,305
ADV
267
44
32
343
AUX
1,746
208
204
2,158
CCONJ
856
127
129
1,112
DET
73
12
8
93
Table 2: Number of tokens per UPOS tag in each data split.
Hyperparameter
Value
Maximum sequence length
256
Batch size
16
Epochs
10
Learning rate
2×10−5
Weight decay
0.01
Dropout
0.10
Table 3: Hyperparameter settings for fine-tuning.
Model
Dev
Test
XLM-RoBERTa base
87.29 ± 0.21
88.60 ± 0.21
Urdu RoBERTa small
85.11 ± 0.14
86.85 ± 0.21
Multilingual DistilBERT
84.44 ± 0.32
86.03 ± 0.30
Table 4: UPOS accuracy (%) over five random seeds, reported as mean ± sample standard deviation.
UPOS
Precision
Recall
F1
Support
ADJ
0.6826
0.7451
0.7125
153
ADP
0.9616
0.9525
0.9570
526
ADV
0.7083
0.5312
0.6071
32
AUX
0.8883
0.8971
0.8927
204
CCONJ
0.8603
0.9070
0.8830
129
DET
0.4615
0.7500
0.5714
8
Table 5: Per-class test results for XLM-RoBERTa (seed 46). Support is the number of gold test tokens.
Gold
AUX
NUM
NOUN
CCONJ
VERB
ADP
PUNCT
ADJ
PART
PROPN
PRON
SCONJ
ADV
DET
SYM
X
INTJ
AUX
183
0
1
0
19
0
0
0
1
0
0
0
0
0
0
0
0
NUM
0
39
3
0
0
0
0
0
0
0
0
0
2
0
0
0
0
NOUN
4
4
911
1
23
7
0
30
0
53
11
4
1
1
0
0
0
CCONJ
0
0
0
117
0
10
0
0
0
0
0
2
0
0
0
0
0
VERB
13
0
26
0
178
0
0
5
1
1
3
0
0
1
0
0
0
ADP
0
1
5
17
1
501
0
1
0
0
0
0
0
0
0
0
0
Table 6: Test-set UPOS confusion matrix for XLM-RoBERTa (seed 46). Rows are gold tags; columns are predicted tags.