This is a common enough word in English. According to the Great Fraud Daniel Cassidy, it comes from the Irish word táille. The truth is that both the English term and the Irish word derive from the Latin talea, a cutting, rod or stick. This is because the original tally was a stick which was cut in two lengthwise with a variety of notches. When the two pieces were reunited, they matched or tallied. These tallies were used as evidence of a financial agreement. This is a perfect example of Cassidy glomming a word which clearly doesn’t come from Irish.