To start with, we are told “The speech of non-native English speakers may exhibit pronunciation characteristics that result from such speakers imperfectly learning the pronunciation of English, either by transferring the phonological rules from their mother tongue into their English speech ("interference") or through implementing strategies similar to those used in primary language acquisition. They may also create innovative pronunciations for English sounds not found in the speaker's first language.” I expect this would make sense if it provided some examples, but without them (or without going and reading the one reference supplied) I don’t see it. What are “strategies similar to those used in primary language acquisition”?
In among the very general remarks about L2 phonology acquisition, we get a sentence on a couple of specific English pronunciation matters: firstly, “English is unusual in that speakers rarely produce an audible release between consonant clusters and often overlap constriction times”. I think the writer meant to say that English speakers rarely produce an audible release between the consonants in consonant clusters. I don’t know of any evidence that English is unusual in this respect, so I would be glad of a reference. Then we get “Speaking English with a timing pattern that is dramatically different may lead to speech that is difficult to understand”. The use of “dramatically” is one of several cases where subjective words are used inappropriately.
Reading further, I have to struggle with “More transparently, differing phonological distinctions between a speaker's first language and English create a tendency to neutralize such distinctions in English, and differences in the inventory or distribution of sounds may cause substitutions of native sounds in the place of difficult English sounds and/or simple deletion. This is more common when the distinction is subtle between English sounds or between a sound of English and of a speaker's primary language”. I don’t know what “More transparently” means here, and more importantly, I don’t understand what is meant by “differing phonological distinctions between a speaker's first language and English”, given that the issue of size of phoneme inventory is mentioned in the next clause. There is more subjectivity in the use of “difficult” and “subtle”, neither of which should be used without explanation.
Finally, we read “… several theoretical models have presumed that non-native speech perceptions reflect both the abstract phonological properties and phonetic details of the native language.” But surely we aren’t talking about perception here?
Since this is the silly season, I will finish with a trivial cross-language observation I have made in France and the UK. There is a company that repairs car windscreens, called Autoglass in the UK and (I don’t know why) Carglass in France. They advertise on TV in both countries, and have a jingle that goes “Autoglass repair, Autoglass replace” in UK and “Carglass répare, Carglass remplace” in France. The English version is sung in 4/4 time, but in French this timing would make it necessary to give two beats to the vowel of “Car”. Since the vowel in “Car” isn’t long in French (which doesn’t distinguish long and short vowels) this wouldn’t be appropriate, so the French version is in 3/4 (Waltz) time, though otherwise identical. I think that is very sensitive of Autoglass/Carglass.