What is the central vowel in phonetic alphabet?

There isn't a single "central vowel" in the International Phonetic Alphabet (IPA). The IPA is a system for representing all the sounds of human language, and vowels are typically categorized based on their height (how high or low the tongue is in the mouth) and frontness (how far forward or back the tongue is in the mouth).

However, there are several vowels that could be considered "central" based on their position in the vowel chart:

* [ə] schwa: This is often considered the most central vowel, as it's produced with the tongue in a neutral position.

* [ʌ] upwards-turned a: This vowel is often considered "central" in English, although it has some backness to it.

* [ɐ] open a: This vowel is a bit more open than schwa, but still considered relatively central.

It's important to note that the "centrality" of vowels is not an absolute concept. The specific position of vowels can vary slightly depending on the language and the speaker.