Lots of existing players at the moment at the Spanish speaking community who prefer not to play in English bought into the game under the expectation that the game at launch would have had the promised localizations, including Spanish:
All stated at Newsletter 34 in Agust 2014:
http://us2.campaign-archive1.com/?u=dcbf6b86b4b0c7d1c21b73b1e&id=8b7e3f3ba9
4 months after release and 8 months after the announcement we still dont have the Spanish localizations.
And many Spanish speaking players have not been able to even start to play the game they bought for that reason. Some have even started wondering if it would have been better for them simply to wait until the first sales hitting the game maybe in Summer or Christmas this year instead.
Other potential commanders were wiser and have simply not bought into the game yet, waiting. The potential market missed here can be significant too.
It would be great if FDEV could at least announce a tentative timeline for this.