tittle

hippunen A small, insignificant amount (of something); a vanishing scintilla; a measly crumb; a minute speck.
puhekieltä Any small dot, stroke, or diacritical mark, especially if part of a letter, or if a letter-like abbreviation; in particular, the dots over the Latin letters (term) and (term).
1590, Bales, The Arte of Brachygraphie (quoted in Daid King's 2001 'The Ciphers of the Monks'):

The foure pricks or tittles are these. The first is a full prick or period. The second is a comma or crooked tittle.

The words "jot" and "tittle" in this passage refer to diacritic marks, that is, dashes, dots, or commas added to a letter to accentuate the pronunciation.

: (the page calls both "a superscript sign (hooklike)" and also a diacritical abbreviation of ":erOld Norse|er" (:erIcelandic) "tittles")

A tittle is more or less the same thing (the dot over an i, for instance), except that it can be traced back to Medieval Latin for a little mark over or under a letter, such as an accent ague or a cedilla. I don't know whether an umlaut is one or two tittles. Maybe it's a jot and a tittle side by side.