Yes, interesting to see those 'heteronyms' (new word to me!) listed like that. I think one learns one's native language (or languages) by a process of absorption, listening, imitation and repetition, so that the pronunciation of words like though, through or thought becomes automatic – depending on where you live, as regional variations (Roger) make a difference and are not 'wrong' per se. An eminent professor from the Guildhall School of Music and Drama, who had been teaching public speaking for fifty years, believed that anyone only had to live in an area for 6-12 months to absorb something of the local accent. He went on to prove his point by getting each of the 6 of us in the group to give a short 2 minute talk on whatever. He then proceeded to tell each of us about our background, we had been brought up, educated, lived and worked, although the last was easy as we were all in the same profession, but he was uncannily accurate!
The American version/s of English owe more to the Latin based English words rather than the (often shorter) Anglo-Saxon base, eg; terminate for end or finish; commence instead of start, and they modified the spelling of many words to suite the sound: color, catalog, traveled etc. I suspect this is one reason foreigners find American English easier than British English.
But whatever – language evolves and changes; who would use the word 'gay' now to describe bright or light-hearted or 'rubbers' instead of erasers (except in England – maybe!). Language is a fascinating subject; it is a pity it is taught so badly in Thailand.