No Spanish voice found on this device, so the audio may sound like an English speaker. Add a free Spanish voice, then reload this page: iPhone/iPad: Settings → Accessibility → Spoken Content → Voices → Spanish. Mac: System Settings → Accessibility → Spoken Content → System voice → Manage Voices → Spanish (Mexico). Windows: Settings → Time & language → Speech → Add voices → Español. Android: Settings → Text-to-speech output → install Spanish.