Black letters with 20 in the bottom right corner. The backs are blank
I can't find images of the Spanish-specific tiles, but I'm confident because:
- the fonts match for both the letters and the number (for at least one version - the photos at Amazon show two different letter fonts)
- the tile values are plausible (Q is 30 in Dabble, for example)
- the rules mention removing these 6 tiles for play in English - except there's no mention of a "ch" tile, leaving a little doubt. Those Spanish tiles to be removed are described in lowercase, while the other tiles and indeed nearly all word games use uppercase. The latest sales description on their website now mentions 8 Spanish tiles, so it's safe to assume the the 2 extras are "ch".
The game was refreshed in 2017 (when this font started to be used), but the rules date back to the 2011 initial release (as they show a typewriter-style font).