Thank you for your feedback.
The tour is clearly titled on Viator as "Cork City, Cahir Castle and Rock of Cashel Tour with Spanish Speaking Guide" the description of the tour details this too, and the ticket confirmation would have shown this as the tour name.
We have not had problems with people turning up expecting English speaking guides so we investigated what happened and it appears if specifically an English language tour was searched for this tour appeared on the listings. This has now been rectified to avoid this happening again.
We apologise for your inconvenience, our guide took time outside of his normally commentary to explain and assist with things in English so hopefully you were still able to enjoy the spectacular sites on the tour.