## 2 Background  
In recent years, research on Kurdish language technology has gained more attraction. Kurdish is spoken by approximately 30 million people [1]. It is a multi-dialect language, and its two most widely spoken dialects, Kurmanji (Northern Kurdish) and Sorani (Southern Kurdish), are spoken by roughly 75% of native Kurds [5; 6]. Sorani usually is written in an adapted Persian-Arabic script with a cursive style and from Right To Left (RTL). Kurmanji mostly uses Latin for writing, except in the Kurdistan Region of Iraq and Kurdish areas of Syria, where they use the same script that Sorani uses [1]. The alphabet of the mentioned script includes 34 letters that appear in different shapes according to their position in words (see Table 1). Kurdish language technology and its challenges have been addressed and categorized as: dialect heterogeneity, script variety, lack of standards, lack of resources, and lack of investment [1; 7; 8]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{**Contextual Form**} \\ \hline \# & **Isolated** & **Initial** & **Medial** & **Final** \\ \hline
1 & - & - & & - & \\
2 & \(\backslash\) & & & \(\sqcup\) & \\  
\hline \hline \end{tabular}
\end{table} 
Table 1: Kurdish alphabet forms, both Ligature and Isolated. Table 2 shows the order of the alphabet of the Persian-Arabic script based on the Kurdish Academy proposal. The Arabic alphabet has 28 letters with a cursive style (see Table 3). The Persian writers augmented the Arabic alphabet to include graphemes for the phonemes that did not exist in Arabic. The Kurdish writers also did the same on the Persian-Arabic version [9]. The augmented scripts are known as Persian-Arabic scripts though the Kurdish one includes more new graphemes for the phonemes than the one that is used in Persian (Farsi) writing. The Kurdish Persian-Arabic script uses 21 out of 28 Arabic letters, keeps all four extra letters added by Persians, and adds nine letters. Seven Arabic letters were found unsuitable for Kurdish because they have no corresponding sound (phoneme) in the language. Unsuitable letters for the Kurdish language are,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,  
As indicated by [PERSON] (1992), the Kurdish alphabet has seven vowels, which are presented with seven corresponding letters (see Table 6). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{4}{c}{**Modified Arabic Letters to Kurdish**} \\ \hline \# & **Arabic Letters** & **TO** & **Kurdish Letters** \\ \hline
1 & \(\searrow\) & & \\
2 & \(\searrow\) & & \\
3 & \(\searrow\) & & \\
4 & \(\searrow\) & & \\
5 & \(\searrow\) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Modified Arabic letters to Kurdish letters. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{4}{c}{**Contextual Form**} \\ \hline \# & **Isolated Form** & **Initial** & **Medial** & **Final** \\ \hline \multirow{4}{*}{1} & * & & \(\dagger\) & \(\bot\) \\  & (used mainly in the medial and final & & & \\  & position, which is an unlinked letter) & & \(\downarrow\) & \(\downarrow\) \\ \cline{2-5}  & & \(\downarrow\) & \(\downarrow\) & \(\downarrow\) \\
2 & \(\downarrow\) & & \(\perp\) & \(\downarrow\) \\
3 & \(\searrow\) & & \(\perp\) & \(\downarrow\) \\
4 & \(\searrow\) & & \(\dash\) & \(\dash\) \\
5 & \(\vartriangle\) & & \(\dash\) & \(\dash\) \\  
28 & & & \(\vartriangle\) & \(\vartriangle\) & \(\vartriangle\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Arabic alphabet. The Kurdish alphabet also uses a specific character named Zero-Width Non-Joiner (ZWNJ) for digital writing. ZWNJ is a non-printing character placed between two characters to avoid inappropriate concatenation. For example, after the character \" \". ZWNJ is encoded in Unicode as U+200C. It is illustrated in the following words:. If ZWNJ was not used, those words appeared as. Optical Character Recognition (OCR) is a research area that benefits from several computing fields, such as machine learning, computer vision, and natural language processing [11].