What is the most common word that starts with 's' and includes 'lph'?A popular word for your search is 'sulphur'.
What is the longest word you can make using words that start with 's' and include 'lph'?Consider 'succinylsulphathiazole'
How many words is it possible to make using this combination of letters?Altogether, you could select from exactly 293 words.
Is there an example word from this page that could be deemed as unusual?Standing as our favorite unusual word on this list is 'sulphostannic'. The definition of 'sulphostannic' is as follows: "Of, pertaining to, or designating, a sulphacid of tin (more exactly called metasulphostannic acid), which is obtained as a dark brown amorphous substance, h". Source Oxford Dictionary.
What is the highest scoring word you can play in Scrabble ?As there are an extensive 293 entries, you should select 'sylphize' which scores 25 points overall.