A tracking specification written in plain English gets translated by a developer, and translation is where specifications drift from what was requested.
Ambiguity costs a sprint
"Track the newsletter signup" leaves the event name, the parameter names and their casing to whoever implements it. Three implementers produce three schemas, and the reporting built on top of them does not match.
Supply the exact strings
Convert the human-readable list to the exact casing the platform expects and put those literal strings in the specification. There is then nothing to interpret, and the implementation either matches the spec or visibly does not.
Name the type separately from the instance
Schema and component names are usually PascalCase while the fields inside them are camelCase. Getting that distinction right in the spec avoids a round of review comments that are purely about formatting.
Try it: Convert to PascalCase on SeoWolf's Notepad.