This page will help you get started with Lexi API.

Lexi is an engine for enhancing the pronunciation of troublesome words. For example, ensuring the city name ‘Reading’ is pronounced correctly. Dictionaries are split into languages and types. For example, the town ‘Reading’ would be of type: location with language: en-gb and would belong, in this case, to the uk_towns dictionary. This API serves for a direct interaction with the dictionaries, however its functionality is embedded in Script and Speech APIs.

Read more about it here: https://docs.api.audio/docs/lexi-dictionary