There's always some logic behind a folk etymology, though. It has to be plausible. For example, if I claimed that the expression 'groovy' was invented by Lord Zorgath, emperor of the planet Yaxelblurg, because he had an obsession with vinyl records and considered their grooved surface the pinnacle of aesthetic advancement, you'd likely have the nice young men in their clean white coats come to take me away. But if I told you that the money given to someone as a gratuity for some service is called a 'tip' because it comes from the phrase 'to insure promptness,' well, you just might believe me (but don't--it's another folk etymology).
In English, competing folk etymologies abound. The globally ubiquitous expression 'OK' is perhaps foremost in sheer number of dubious claims of origin, but expressions like "mind your Ps and Qs", and the curse words that begin with f and sh respectively have plenty of colorful stories purporting to capture their true origins, too.
Much of the time, the true etymology of a word is just plain boring by comparison. And as it happens, most folks don't know the details of sound changes and semantic shifts and derivations and inflections that drive language change. So folk etymologies are born. Someone wonders about the origin of this word or that phrase, and comes up with what seems like a logical story. And even in the face of linguistic evidence, people may still want to believe the more interesting version. So folk etymologies persist.
It's no surprise, then, that Thai has folk etymologies, just like English. One I've heard is for the word ทุเรศ. A quick check in RID99 returns this definition:
ทุเรศ (ปาก) คําพูดแสดงความรู้สึกเมื่อประสบสิ่งที่ขัดหูขัดตาหรือเป็นที่น่าสมเพชเป็นต้น.The claim of the folk etymology is that this expression comes from the English phrase 'too late'. Now, I understand that 'too late' is used by some Thais as a way of disguising the word ทุเรศ, just like some write 'กวน teen' in place of กวนตีน. It gives it a lighthearted or humorous angle, and can help take the edge off of the word's potential impoliteness. So it's possible that some (or many) folks are only using it to be ironic or funny. Nevertheless, some attempt to claim 'too late' as the legitimate origin of the Thai word.
/thureet/ colloq. An expression to show the feeling of when one experiences something displeasing, or deplorable, etc.
The claim is that Englishmen came to Siam and set up businesses which employed native Thais. These Thais were not used to the strict timekeeping of the Westerners, and so when they failed to show up to work on time they were told they were "too late" by their English-speaking bosses. The Thais heard "too late" as ทุเรศ, which came to be a term indicating disagreeable or unacceptable behavior, etc.
Nitaya Kanchanawan does a good (and very polite) job of eviscerating this theory, which she heard on TV, in her column มองไทยใหม่ in Matichon Weekly (มติชนสุดสัปดาห์, April 28, 2006, p. 76). You can read my translation of that column here, including the original Thai.
Let's take a closer look at how this folk etymology should have been debunked, and definitely should not have made it onto the Thai airwaves, especially as part of a show about preserving Thai culture, as Dr. Nitaya states in her column.
The first evidence is from the spelling. ทุเรศ looks very much like a Thai spelling of an Indic word. It's true that it does not look much like a native Thai word, but it certainly does not look like an English word. The ร does not match the l in English 'late', and the final consonant ศ is usually a sure sign of an Indic loan.
Anyone who has experience with Thai poetry and classical literature (and all Thais do during their years of compulsory education), the ending เอศ should be familiar. It is one of the optional endings which can be compounded with a root to create a poetic version of a word, maintaining the original meaning. This would be done either for rhythm or rhyme's sake. This sort of compounding for the sake of rhyme is referred to as เข้าลิลิต, and in the case of the suffix เอศ, it's called เติม ศ. เข้าลิลิต.
I've translated a passage explaining this poetic device from this site:
เติม ศ. เข้าลิลิต refers to appending the -อีศ (SKT īśa) to the end of a word without changing the meaning, for the benefit of composition, e.g. to increase the number of syllables, or to give a word a low tone (in fact, it usually results in a falling tone, but since it is a dead syllable, it can be used in place of a low tone), or to make a heavy syllable [i.e. a syllable with a long vowel or final consonant], as needed.The Sanskrit īśa becomes Thai เอศ, for example, Sanskrit kamala- īśa becomes Thai /ka-ma-lê:t/ (กมล + เอศ = กมเลศ).
This is a clear model for ทุเรศ to follow, which we would expect to be made up of ทุร- and เอศ. And what do you know! RID99 quickly gives up the likely culprit:
ทุร- [ทุระ-] ว. คําประกอบหน้าคําศัพท์ หมายความว่า ชั่ว, ยาก, ลําบาก, น้อย, ไม่มี, เช่น ทุรค ว่า ที่ไปถึงยาก, ทางลําบาก. (ส.).This fits the meaning of modern ทุเรศ quite well. It's seen in compounds like ทุรกันดาร (as in ถิ่นทุรกันดาร 'wasteland'), and is the etymological sibling of the prefix ทร- (as in ทรราช 'tyrant', ทรยศ 'betray', ทรมาน 'torture'). The semantic connection with the modern colloquial usage of ทุเรศ is clear enough.
/thura-/ adj. A prefix meaning evil, hard, difficult, few, none, e.g. ทุรค 'a place difficult to reach, a difficult path' (Skt.).
The second line of evidence is text citations. RID99 falls short on this particular entry, even failing to note the word's Indic origin. Fortunately, Matichon Dictionary comes to the rescue:
ทุเรศ ว. ยาก, ลำบาก, เช่น เราแจ้งทางทุเรศเขตอรัญ สัตตภัณฑ์คั่นสมุทรใสสี (กากี). ก. หลีกลี้ไปไกล, ไปห่างไกล, เช่น หมู่สุบรรณพันโกฏิในสิมพลี ทฤษฎีแล้วทุเรศจากสถาน (สมบัติอมรินทร์). (ปาก) ว. อุจาด; คำพูดแสดงความรู้สึกว่าสิ่งนั้นๆ บุคคลนั้นๆ หรือการกระทำนั้นๆ เป็นที่น่าสมเพชหรือขัดหูขัดตา.Matichon includes two citations, both dating from the reign of Rama I (1782-1809). The nails are starting to go into the coffin of this folk etymology. From these citations alone it becomes utterly unlikely that a well-formed Thai poeticism would have anything to do with English, but indulge me in eliminating any possibility.
/thureet/ adj. Difficult, troublesome, e.g. เราแจ้งทางทุเรศเขตอรัญ สัตตภัณฑ์คั่นสมุทรใสสี (กากี). v. flee far away, go far away, e.g. หมู่สุบรรณพันโกฏิในสิมพลี ทฤษฎีแล้วทุเรศจากสถาน (สมบัติอมรินทร์). (colloq.) adj. disgusting; an expression to show the feeling that a thing or person or action is deplorable or displeasing.
The earliest contact of British traders with Siam that I can find record of is a meeting of Captain William Keeling of the East India Company with an ambassador of Siam at the Javanese city of Bantam in 1608*. This doesn't yet approach setting up businesses and hiring Thai employees on Siamese soil, but we can confidently say that there was no possibility of such a situation taking place with English speakers prior to 1608. A citation of ทุเรศ prior to 1608 should close the case on the origin of this phrase. And Dr. Nitaya is the one who provides it, from the same article linked above:
If we go back to the time of King Trailokanat of Ayutthaya, we find that he ordered a meeting of royal scholars to compose the Mahajati, in the year 1482.In fact, 1482 predates the earliest known contact with any Western nation, the first being Portugal in 1511. The 'too late' folk etymology makes for a good story, but it turns out that's all it is.
In the Matsi Sermon, when Princess Matsi reproaches Prince Wetsandon for giving their two children to Chuchok, the passage reads:"Princess Matsi responded, when the Prince had given her two true friends as alms, 'Why do you torture me? For what purpose do I suffer to go about in search of them throughout the night?"This passage shows that /thureet/ has been used since the Ayutthaya period, and also probably before the establishment of farang businesses.
[Original Thai is here. I'm not extremely confident about my translation of the passage. Corrections welcome.]
*Anderson, John. 1890. English Intercourse with Siam in the Seventeenth Century, p.46. [Downloadable via Google Books within the United States, as far as I know. I have the PDF saved offline.]