The difficulty for ESL learners in acquiring syllable codas stems from a combination of linguistic, phonological, and cognitive factors.

1. Limited Phonological Inventory: Many ESL learners come from language backgrounds with a different set of phonemes and syllable structure compared to English. Some languages may lack certain consonant clusters present in syllable codas in English, making it challenging for learners to produce and perceive these sounds accurately.

2. Transfer from L1: When ESL learners transfer their phonological patterns from their native language (L1) to English, they may experience interference. In some cases, syllable codas in English may contrast with those in the learners' native language, leading to pronunciation difficulties and accent-related challenges.

3. Syllable Structure Complexity: English has a relatively complex syllable structure, including a wide variety of consonant clusters in syllable codas. ESL learners may struggle with the coordination of multiple consonants at the end of syllables, affecting both production and perception.

4. Phonotactic Constraints: ESL learners may find it challenging to conform to the phonotactic constraints of English, which govern the permissible combinations of sounds within a syllable. Syllable coda clusters in English often require precise articulatory coordination, which can pose difficulties for learners.

5. Acoustic and Perceptual Differences: Some syllable codas in English involve subtle acoustic distinctions that ESL learners may find difficult to perceive. Additionally, distinguishing between different coda clusters can be demanding for learners due to variations in articulatory gestures.

To address these challenges, ESL instructors often employ instructional strategies that focus on phonological awareness, articulation practice, and explicit instruction on syllable structure. By providing targeted feedback and opportunities for phonological practice, ESL learners can improve their proficiency in mastering syllable codas in English.

Its because some of the prominent sounds in English language do not exist in their own mother tongue.Hence its difficult for them to not only produce those sounds, but also to identify them and divide them into appropriate syllables.

Exactly.

I agree with the comments above. My recommendation is to create a contrastive analysis of articulatory features of students' First and Target Languages, such as place and manner of sounds' articulation, especially of those that differ, paying attention to the position of tongue, specifically to its parts, during articulation of each sound (that is, which part of the tongue - its tip, blade, middle or back part is involved in articulation; whether the tongue is flat or curved, focusing also on location and height of the curve in the mouth cavity).