This is a legitimate word you know. Although it should be spelled with 2 "d's".
glad·den Pronunciation Key (gldn)
v. glad·dened, glad·den·ing, glad·dens v. tr.
To make glad. See Synonyms at please.
v. intr. Archaic
To be glad.
Source: The American Heritage® Dictionary of the English Language, Fourth Edition
a. cricket
As for things like "nu-cyoo-lar", such variations in pronunciation are a common aspect of most dialects [to those who would suggest that he should know that "nuclear" is derived from "nucleus", I would respond, "nu-cyoo-lus"?]
Actually, "nucleo/nucleu" step is nearly unique (if not totally so) in having a "cl" double-consonant following a long "oo" vowel. Such a double consonant can be very difficult to say, and can easily pick up an extra syllable (e.g. as "jewelry" is often pronounced "jool-er-y").
Adapatations of language to pronouncibility are hardly a recent phenomenon. Certain consonantal changes have occurred in different languages over hundreds of years following their spinoff of Indo-European. Consider the consonant pairs (p,f) and (c,g) and examine some common words in different languages: (pices,poisson,fish) or (cat,gato), etc. While the usages are standardized today in the different languages, there clearly were shifts in pronunciation over time.
To be sure, one should try to avoid sounding like a moron when speaking. But many of the interesting aspects of Bush's speech patterns are part of a common shift in pursuit of pronouncibility.
[BTW, I believe formalism is generally much more important in writing than speech; I accept and use many colloquialisms in speech I wouldn't dream of writing except as part of a dialogue.]