Error Type 1: /r/

This consonant doesn’t exist in Thai, so it’s usually either replaced with a sound similar to /l/ in English when it’s the initial sound of the word and substituted for /ɹ/ or omitted altogether after other consonants such as /p/, /t/,/b/, /d/, /f/, /k/, /g/, /θ/, or rarely /ʃ/.

Finally, /r/ is usually omitted in the middle or at the end of
a word when it succeeds a vowel.

/r/ (beginning): right; race; really; red etc.
/r/ (after consonants): problem; traffic; brother;
drive; frog; crawl; great, three etc.
/r/ (end): car; meter; prefer; bear; fear etc.

Error Type 2: /l/

This consonant has an equivalent in but it can only be found at the beginning of a word. After consonants /p/, /b/, /f/, /k/, /g/, /or /s/, the /l/ can either be replaced by /r/ or /ɹ/ or completely deleted.

When Thai learners pronounce a word containing /l/ in the middle, they move their lips forward generating a consonant /w/, sometimes followed with /r/ or /ɹ/ while others produce nothing.

When /l/ happens to be the last consonant of a word, it’s usually inaudible either because it’s been deleted or replaced by /w/.

/l/ (beginning): light; lace; lead; laugh; learn etc.
/l/ (after consonants): please; blue; fly; close; glue;
slow etc.
/l/ (middle): fault; rolling; falling; swollen; really etc.
/l/ (end): recall; fall; roll; available; identical etc.

Error Type 3: Consonants Cluster

Thai learners have trouble producing any pair or group of consecutive consonants known as consonant clusters such as /ks/, /gz/, /ts/, /st/, /dz/, /str/, /pl/, /kr/, and /bz/.

Consequently, some consonants in these clusters can either be substituted or omitted.

Needless to say, consonant clusters can be found at the beginning,
middle or end of a word.

Consonant clusters: rocks; bags; seats; steak;
roads; strike; plural; crow; slabs etc.

Error Type 4: Confusion with stops, fricatives and affricates

Stops or plosives are consonants for which we abruptly and utterly block the airflow such as /k/, /g/, /t/, /d/, /p/, and /b/.

Thai learners, in particular, struggle with ending the words with such consonants.

As a result, the stop consonants are either omitted or replaced by a fricative, for example, /t/ and /d/ could be replaced by /s/, /z/ or even /θ/ or /ð/, while /p/ could be substituted for an equivalent to /f/ and /b/ for /d/.

Bear in mind that just as fricatives can replace stops, the latter can replace the former. Perhaps the most difficult manner of articulation is the affricates such as /dʒ/ and /tʃ/ especially in the middle and at the end of the word.

Words ending with stops: cake; beg; cute; bird;
scoop; rehab;

Words ending with fricatives: case; rise; enough;
dive; change; month; writhe; rush etc

Words ending with affricates: catch; manage;
coach; engage etc.

Error Type 5: Voicing & De-voicing

Thai learners, like many others, have no grasp of the concept of voicing and de-voicing the English consonants, so /v/ is turned into /f/, /g/ to /k/, /d/ to /t/, /z/ to /s/ and /b/ to /p/.

In some cases, the opposite is also true, where for example /t/
becomes /d/ and /θ/ becomes /ð/. This essentially depends on the vowels preceding or succeeding the consonants.

Words with /v/: video; lover; crave
Words with /g/: go; rugged; bag
Words with /d/: door; video; rude
Words with /z/: zero; isn’t; booze
Words with /b/: ball; trouble; globe
Words with /ð/: the; weather; with
Words with /f/: fine; laughter; enough
Words with /k/: kill; rectangular; back
Words with /t/: tour; attain; root
Words with /s/: sign; mister; voice
Words with /p/: pole; leopard; rope
Words with /θ/: thigh; ether; earth

Error Type 6: /tʃ/ & /ʃ/

Although we have already touched on the source of this problem in TYPE 4, it’s worth re-visiting and highlighting it as a separate error.

Thai learners can use /tʃ/ & /ʃ/ interchangeably.

For example, they can pronounce the word [wash] as [watch] but the word [cheese] as [she’s].

It’s normally difficult for Thai learners to begin a word
with /tʃ/.

Words beginning with /tʃ/: child; chow; chest;
check; chill; chop etc.

Words with /ʃ/ in the middle: cashew; rushing;
facial; tension; crucial etc.

Words ending with /ʃ/: sash; gush; crash; mash;
harsh; foolish; cash etc

Error Type 7: /n/

Thai learners are able to begin and end a word with /n/ but certainly seem to have trouble pronouncing it in the middle of a word and when it succeeds diphthongs such as /aʊ/ /oʊ/ /ɔɪ / /eɪ /and /aɪ /.

What Thai learners do normally is nasalize these diphthongs instead placing the tongue to against the ridge and blowing air through the nose.

Please note that when learners pronounce the /n/ at the beginning of the word, they sometimes place the tip of their tongue between their teeth, which is also incorrect.

/n/ (beginning): not; nine; novice; nickel; nest;
never etc.

/n/ (after diphthongs): around; loan; point; train;
fine etc.

/n/ (end): person; station; melon; fun; Helen; warn etc.

Error Type 8: Nasalized Vowels

Teachers need to bear in mind that Thai learners produce most of the vowels nasally even when there’s no /n/, /m/, or /ŋ/ in the word.

This is due to the nature of the Thai language that is mostly nasal.

What this means for example is that even when the learners pronounce /i:/, it’ll come out nasal, so will the rest of the vowels.


Error Type 9: /w/ & /v/

When followed by /e/, /ɔ:/, /oʊ/, and /ɝ/ in particular, Thai learners are not able to produce the English consonant /v/ accurately as it’s very difficult for them to move their lower lip up independently to touch the upper teeth while holding the upper lip utterly still.

By the same token though, they are not able to produce the English /w/ properly either when it’s followed by /i/ or /ɪ / as they involuntarily change it to /v/.

/v/ followed by vowels /e/ /ɔ:/ /oʊ/ /ɝ/: very; volt;vote; verb etc.

/w/ followed by vowels /i/ & /ɪ/: wheat; we; will; wit etc.

Error Type 10: /eɪ/ & /aɪ/

When /eɪ/ or /aɪ/ appear in the end of the word, Thai learners are able to produce them but nasally; however, when they’re situated between two consonants, the /eɪ/ becomes /e/ and /aɪ/ becomes /a/.

The first thing that a teacher should do to assist Thai learners in producing these diphthongs properly is to de-nasalize them during
correction through focusing on using the diaphragm.

Words with /eɪ/ between consonants: train; bait;
wait; fate; raise etc.

Words with /aɪ/ between consonants: tried; wife;
side; mine; file; ride etc.

Error Type 11: /oʊ/

As with most Asian learners, Thai learners have great difficulty pronouncing diphthongs such as /oʊ/ as it ends with /w/.

Although Thai learners move their lips forward to produce /ɔ:/, they fail to round their lips tight enough for consonant /w/ that follows.

/oʊ/: go; wrote; boat; sew; dope; coat; throne etc.

Error Type 12: /ɝ/

Thai learners replace this vowel with a Thai phoneme that has no equivalent in English.

It may sound fairly close to the British /3/ to many teachers but the fact is that there is even a difference in breathing the sound and utilizing the vocal chords.

When Thai learners attempt to produce this sound, the tongue is positioned somewhere between /3/ and /e/ and the lips do not make any forward movement.

Please remember that vowel /ɝ/ comprises consonant /r/ which Thai learners are not normally able to pronounce.

/ɝ/: first; service; bird; curl; heard; work; merlin;
girl etc.

Error Type 13: / θ/ & /ð/

The lingua-dental consonants are notoriously difficult for all English learners including Thai students as they require the tip of the tongue be placed between the teeth without biting and for the air to come out through a very narrow passage essentially between the tongue and upper teeth.

Thai learners substitute /ð/ for /d/ or even /t/ when de-voiced and /θ/ for /t/.

/θ/: thin; wrath; moth; thigh; Ruth; truth etc.

/ð/: weather; loathe; then; writhe; scythe; rather