In the isle of dick case, there were two unrelated words,
- one with a long o, a placename, the accent marks the vowel as long, and
- one with a short o, "bod", the word for penis (pronounced like English "pot" but with no aspiration on the /p/ or /t/, and the t is dental, so sounds we don't have in English at all)
So accent dropping, changing long vowels into short ones, is bad, as you easily pick unrelated words. I once spent an evening referring to a woman as "nipple" again and again because I got a vowel length wrong in her name. Bewildered looks, as a native speaker struggled to try and work out what on earth was going on.