Bob, just to keep the record straight, I majored in English for about three years before I changed my major to Music. Having been a word-buff all my life, I'm a veritable mine of etymology. I know a great deal about changes in the alphabet, changes in word usage, changes in pronunciation, changes in grammar, and the general history and growth of the English language. Checking again with my wife (a writer and editor who once worked in all phases in a publishing company, including type-setting, and who now works for the Seattle Public Library) she reasserts that many of the type-face combinations no longer in use -- and punctuation conventions still in use that don't necessarily make sense -- come from the fact that many printers used wooden type, and it was pretty delicate. Parts of letters, particularly letters that protruded above or below the letters adjacent, kept breaking off, so certain combinations of letters were cut on a single block, sometimes with a modified shape, so they would reinforce each other. "st" and "sl" were two such combinations. What you say about the differences in pronunciation between the two "s"s is true, but that worked out felicitously for printers who used wooden type.

A little historical trivia.

Don Firth