Ask for inflections separately.

For instance, in many Japanese forms, there are dedicated fields for the name and the pronunciation of the name. There are possibly multiple ways to read a name (e.g. 山崎 is either やまざき or やまさき). It is better to ask the person "how to read your name?" rather than execute code to guess the reading.

As for transliteration, it's best to avoid if possible. If not possible, then rely on international standards (e.g. Japanese has ISO 3602 and Arabic has ISO 233-2). When international standards don't exist, then fall back to "context-dependent" standards (e.g. in Taiwan, there are several variants of Pinyin. Allow the user to choose the romanization that matches their existing documentation).