One more time!

When speaking English and saying the plural form of a Spanish surname, the name gets said the same as the singular form.

A right-speaking English speaker says “Juan Valdez”, “Juan and Juanita Valdez” and “The Valdez”.

When speaking Spanish and saying the plural form of a Spanish surname, the name gets said the same as the singular form. However, the singular masculine or feminine definitive article, depending upon the name, gets changed to the plural definitive article.

So the Spanish speaker says, “Juan Valdez”, “Juan y Juanita Valdez” and “Los Valdez”.

Valdez is not an English loan word. Thus, the word gets said as a native speaker would say it.

correction:

When speaking English and saying the plural of a Spanish surname, the name gets said the same as the singular.

A right-speaking English speaker says “Juan Valdez”, “Juan and Juanita Valdez” and “The Valdez”.

When speaking Spanish and saying plural of a Spanish surname, the name gets said the same as the singular. However, the singular masculine or feminine definitive article, depending upon the name, article gets changed to the plural definitive article.

So the Spanish speak says, “Juan Valdez”, “Juan y Juanita Valdez” and “Los Valdez”.

Valdez is not an English loan word. Thus, the word gets said as the native speaker would say it.

When speaking English and saying plural of a Spanish surname, the name gets said the same as the singular.

An right-speaking English speaker says "Juan Valdez", "Juan and Juanita Valdez" and "The Valdez".

When speaking Spanish and saying plural of a Spanish surname, the name gets said the same as the singular. However, the singular masculine or feminine definitive article, depending upon the name, article gets changed to the plural definitive article.

So the Spanish speak says, "Juan Valdez", "Juan y Juanita Valdez" and "Los Valdez".

Valdez is not an English loan word. Thus, the word gets said as the native speaker would say it.