I did a Web search on this and found this site:
https://www.wolfram.com/lan uage/11/text-and-language-processing/frequencies-of-letters-vs-first-letters.html
You can’t click on it. You will have to do a copy and paste.
Don’t get bogged down in the code. What I found of interest were the two tables. The first shows how many times each letter comes first. The second shows how many total times that the letter appears.
If consonants and vowels were completly randomly distributed, we would expect the 5 vowels (for simpiicity I am ignoring y), out of 26 =5/26, a little under 4%. Vowels show up more frequently than that because every syllable has at least one of them. According to the data in the Web site, vowels overall appear 40% of the time.
If we just look at how frequently vowels appear at the beginning of words, the rate is 20%. In the case of people’s names, it seems that vowels do even more poorly at the start of the name, for example looking at the 11% for presidential last names.