The OFFICIAL Estonian alphabet has 27 letters: A, B, D, E, F, G, H, I, J, K, L, M, N, O, P, R, S, Š, Z, Ž, T, U, V, Õ, Ä, Ö, Ü.
The letters F, Š, Z, Ž are so-called “foreign letters” (võõr/tähed), and occur only in loan words (laen/sõnad) and foreign proper names. Occasionally, the alphabet is recited without them, and thus has only 23 letters: A, B, D, E, G, H, I, J, K, L, M, N, O, P, R, S, T, U, V, Õ, Ä, Ö, Ü.
Additionally C, Q, W, X and Y are used in writing foreign proper names. They do not occur in Estonian words, and are not officially part of the alphabet. Including all the foreign, unofficial letters, the alphabet then consists of the following 32 letters: A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, Š, Z, Ž, T, U, V, W, Õ, Ä, Ö, Ü, X, Y. So it's only in the unofficial version, that the Estonian Õ and so-called täpi/tähed (“dot letters”) are not at the very end, but give way to a few visiting guests.
In the early 20th century, keele/teadlane (philologist) Johannes Aavik suggested replacing the letter Ü with Y, as in the Finnish alphabet, but we still have our great smiling Ü wrapping up the parade.
Riina Kindlam, Tallinn