Although English is more widely spoken on Utila [1] than Spanish, the Central American Spanish School (tel. 504/425-3788, www.ca-spanish.com [2]) offers popular and recommended Spanish classes on Utila for US$150 a week for 20 hours of private classes or US$100 for 20 hours of group classes (discounts are often available for the private classes).
CASS has its main office in La Ceiba [3], with offices in Roatán [4], and Copán Ruinas [5] as well, and can arrange monthlong programs combining a week on Utila with a dive course, two weeks of classes, and a homestay in La Ceiba, and a week of classes and homestay in Copán. It is east of the municipal dock opposite the water.
Links:
[1] http://www.moon.com/destinations/honduras/the-bay-islands/utila
[2] http://www.ca-spanish.com
[3] http://www.moon.com/destinations/honduras/the-north-coast/la-ceiba
[4] http://www.moon.com/destinations/honduras/the-bay-islands/roatan
[5] http://www.moon.com/destinations/honduras/western-honduras/copan-ruinas