Currently, the Web Payments SDK does not provide a way to update the aria-labels for the input fields, which makes the screen-readers read the placeholders instead.
For the expiry field, screen readers read it as MM, YY which isn’t helpful and caused problems to a customer recently.
It would be great to have this API for accessibility purposes.
We’re constantly working to improve our features based on feedback like this, so I’ll be sure to share your request to the API product team. What was the customer expecting to get or what would have been more helpful so I can pass this on to the team. 
Thanks for the quick response @Bryan-Square
You can find the details of the issue reported here - Accessibility Concern: Potential Issue for Visually Impaired Users | WordPress.org
Okay, this is with the WordPress integration. They own that integration and its good that you reached out to them.
Yeah. As per the development team, this is not something that can be handled within the WordPress integration, as the credit card fields are part of the iframe. To resolve this, the Square Web SDK has to provide an API such that the aria-labels can be set. Do you think this could be a reasonable feature request?
I’ll pass this on to the team.