Phonology

Cambridge dictionary defines Phonology as: “the study of the pattern of speech sounds and the study of sounds in particular language or in languages generally” ( (Meaning of phonology in English).Phonology means how the sounds of a certain language, are organized to form words. (Shalabi, 2017)

Having perfect Pronunciation is the most important skill in communication. (Karakas, 2011) . Teachers ,educators and phoneticians learns phonology to help the speakers master perfect pronunciation of the sounds .Phonology helps  to identify the difficulty in learning the sounds of other languages.  (Susanto A. , 2012)

Learning English can be frustrating for ESL and EFL learners because they face difficulty to pronounce new sounds while teaching (Hudson, 2016)  .Moreover, the influence of the native language which sometimes hinders the foreign learners to master the pronunciation of sounds in the target language. (Gashaw, 2015)

Most EFL, ESL and even the native speakers struggle to pronounce the voiced and the voiceless interdental fricative (/ð/) /θ/ sounds where the tip of the tongue is placed between the lips (PESCE) , (Gashaw, Perceptions of English Segmental Phonemes by Ethiopian EFL, 2017)

Telegraph news mentioned that by 2066 the /th/sound will disappear in UK because foreigners are having hard time learning to master this sound perfectly. (Knapton, 2016)

Many foreigners substitute these sounds (/ð/) /θ/) with the nearest sound in their language (Subandowo).The process of substitution in phonology is called reverse lisp (Hancock, 2017)

In general, the voiceless dental fricative ‘doesn’t require the vibration of the vocal cords when we produce it .Many foreigners substitute /θ/ with: /s/, /t/, /f/, /b/, while the/ð/ is voiced dental fricative which requires the vibration of the vocal cords. Foreigners substitute the voiced /th/ with: /z/, /d/, /f/ (speaking, 2012)
References:

Hancock, M. (2017, 11 28). Replacing ‘th’: The reverse lisp. Retrieved 4 2019, 29, from Cambridge University Press: http://www.cambridge.org/elt/blog/2017/11/28/replacing-th-the-reverse-lisp/

How to Pronounce the TH Sound in English. (n.d.). Retrieved from Yes school: https://www.yes-school.de/how-pronounce-th-sound-english

Hudson, J. (2016, 11 26). Retrieved 4 29, 2019, from TH – the Tooth Sounds: https://pronunciationstudio.com/th-tooth-sounds/

Karakas, A. (2011, 5 7). The Teaching of [θ] and [ð] Sounds in English. Retrieved 4 2019, 29, from Academia.edu: https://www.academia.edu/1753895/The_Teaching_of_θ_and_ð_Sounds_in_English

Knapton, S. (2016, 9 29). Th' sound to vanish from English language by 2066 because of multiculturalism, say linguist. Retrieved from Telegraph news: https://www.telegraph.co.uk/science/2016/09/28/th-sound-to-vanish-from-english-language-by-2066-because-of-mult/

linguistic for Teachers. (n.d.). Retrieved from https://linguisticsforteachersofells.weebly.com/

Meaning of phonology in English. (n.d.). Retrieved 4 2019, 29, from Cambridge Dictionary: https://dictionary.Cambridge.org/dictionary/english/phonology

PESCE, C. (n.d.). Worst Pronunciation Mistakes ESL Students Make Around the World. Retrieved from Busy Teacher: https://busyteacher.org/14846-7-worst-pronunciation-mistakes-esl-students-make.html

Saidi, A. (n.d.). The Importance of Phonetics and Phonology in the Teaching of Pronunciation. Retrieved from Academia.edu: https://s3.amazonaws.com/academia.edu.documents/38871415/The_Importance_of_Phonetics___Phonology_in_the_Teaching_of_Pronunciation.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1556533938&Signature=RNIx1tNZ3UJiS0ObCsGqj5Mkszg%3D&response-content-disposit

Shalabi, M. M. (2017, 5 15). Think, Tink or Sink, the Phonological Awareness of English Voiceless Interdental Fricative [θ] and [ð] Among Chinese, Arab and Pakistani Learners of English. Retrieved 4 2019, 29, from .American Journal of Education and Information Technology: http://www.sciencepublishinggroup.com/j/ajeit doi: 10.11648/j.ajeit.20170101.12

speaking, C. (2012). Be Distinct: The Voiced and Voiceless /th/. Retrieved 4 29, 2019, from Clearly speaking: http://clearly-speaking.com/pdf/th-sound.pdf

Susanto, A. (2012). THE IMPORTANCE OF ENGLISH PHONOLOGY FOR ENGLISH AS FOREIGN LANGUAGE (EFL) TEACHERS. Retrieved 4 29, 2019, from Academia.edu: https://www.academia.edu/5923389/THE_IMPORTANCE_OF_ENGLISH_PHONOLOGY