There is no Spanish-friendly version of the Google Play app that is available for download. However, you can change the primary language that Google Play is displayed in.
Google Play automatically uses your location to find a primary language. Unfortunately, if you live in a multilingual country, there is a fair chance that this "one size fits all" solution will not be beneficial. In order to change your primary language, simply go to the Google account settings page and click the Language & Input Tools link. Then sign in and change your preferred language. This allows any Google Play Store to be Spanish-friendly when you sign in with your specific Google account.