Diphthong Lyrics

As a lover of linguistics, I'm intrigued by the logistics
Of the oral peril lurking when a word's embarked upon
But when twisted vowel and consternance are gone
One word gives more grief than all of the remaining lexicon

Is it the diphthong in "Goodbye" that makes it difficult?
Or do the D and B conspire to trap your tongue?
Or is the G right at the start what tends to be the awkward part
That catches in your throat before the word has yet begun?
On paper its phonetic structure's not atypical
And yet the glibbest wits still choke on it each day
If not the diphthong in "Goodbye", it makes no sense why
We seem to find it such a tricky word to say

While "Help" and "Sorry" challenge some
One word can leave me dumb
Every time I try, like now, to say "Goodbye".