It’s possible to cut that formula nearly in half. Instead of searching for each letter twice—once at the start of the string, and again at the start of a word—search for both combinations at the same time. Here’s an example just using “a”:
REGEX_REPLACE({Field Name}, "^a| a", " A")
Expand that out to cover the rest of the alphabet, then trim the result to get rid of any leading space:
TRIM(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE(REGEX_REPLACE({Field Name}, "^a| a", " A"), "^b| b", " B"), "^c| c", " C"), "^d| d", " D"), "^e| e", " E"), "^f| f", " F"), "^g| g", " G"), "^h| h", " H"), "^i| i", " I"), "^j| j", " J"), "^k| k", " K"), "^l| l", " L"), "^m| m", " M"), "^n| n", " N"), "^o| o", " O"), "^p| p", " P"), "^q| q", " Q"), "^r| r", " R"), "^s| s", " S"), "^t| t", " T"), "^u| u", " U"), "^v| v", " V"), "^w| w", " W"), "^x| x", " X"), "^y| y", " Y"), "^z| z", " Z"))
Too bad that Airtable’s regex variant doesn’t support the \U substitution token. That will replace a given item with its uppercase equivalent, which would make it possible to shrink that formula down to this:
REGEX_REPLACE(Words, "(^.| .)","\\U$1")
To be clear, that last formula WILL NOT WORK in Airtable. It’s just wishful thinking.
