# Translating Speech to Indian Sign Language Using Natural Language Processing
## 3 Comparison  
As shown in Table 3, most of the existing models which convert English text to a sign language [16], whether it is BSL, ASL, or ISL, use natural language processing. The major problem which almost all the existing models face is that the conversion of text to sign language only happens if the sign language for that particular word is present in the database.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Source** & **Objective** & **Methodology** & **Conclusion** \\ \hline \multicolumn{4}{c}{Sign Languages in English} \\ \hline
[17] & Converting the English language to SIGML representation. & The system uses NLTK for the direct mapping of English text to the HamNoSys string. & The system successfully converts input to a small set of HamNoSys strings and then represents them using SIGML. \\ \hline
[18] & Converting English text to ISL using LCTS notation. & The system utilizes various NLTK processes to carry out the conversion. & The system is successful in showing English text in LCTS notation. \\ \hline
[19] & Converting Indian Sign Language to English text. & The system uses various convolutional neural network techniques. & The system is able to convert sign language to the English language for a very small dataset. \\ \hline
[20] & Converting English to animated sign language as per American Sign Language. & The system takes input by using various speech recognition software and then uses various algorithms to produce animated signs. & The proposed system is still in development and will map each word directly. \\ \hline
[21] & A system to translate English to ISL. & The authors use various NLP and Google APIs. & The system takes input in English and with a 77\% accuracy and it converts the input to SIGML animation, but the system is only shown to convert words or letters. \\ \hline
[22] & Generating HamNoSys signs from the user’s input. & The authors use the direct mapping of only 100 words to generate the HamNoSys signs. & The system successfully generates SIGML animation for 100 words in the ISL dictionary. \\ \hline
[23] & A two-way communication system between English and ISL. & The authors use neural network techniques and the HMM model. & The authors only describe the English to ISL in this paper and the system only generates output if the input is an exact match with their database. \\ \hline
[24] & WordNet-based English to ISL gloss. & The authors utilize various techniques and the hidden Markov model. & The system removes the words for which it does not find any replacement in the current database. In addition, the system is the only text to text conversion. \\ \hline
[25] & A two-way communication system between hard-of-hearing and hearing people. & The authors utilize various machine learning algorithms and NLP techniques. & The system only shows ISL signs for those words which are stored in the database and skips any other word. \\ \hline \multicolumn{4}{c}{Sign Languages in Other Languages} \\ \hline
[26] & Converting Arabic text to Arabic Sign Language. & The system uses various parsing and word processing techniques. & The system successfully converts Arabic text to Arabic sign language with 87\% efficiency and then shows the corresponding sign language animatedly. \\ \hline \hline \end{tabular}
\end{table}
Table 3: Literature Survey.  
Our model not only overcomes the problem mentioned in the previous paragraph but also takes it one step further by converting and displaying sign language for phrases/sentences, i.e., if the input from the user has any combination of words for which there is a particular sign present in the ISL database then the proposed system will display the sign for those combinations of words in one go.