There are a few possible reasons why sound is only coming out of the ear speaker on your iPhone:

• Dirt or debris blocking the speaker: If the speaker is blocked by dirt or debris, it can prevent sound from coming out. You can try cleaning the speaker with a soft brush or a can of compressed air.
• A software glitch: A software glitch can also cause sound to stop coming out of the speaker. You can try restarting your iPhone to fix the glitch.
• A hardware problem: If the speaker is damaged, it will need to be repaired or replaced. You can take your iPhone to an Apple Store or an authorized Apple service provider to have it checked out.

Here are some additional things you can try to fix the problem:

• Make sure that the volume is turned up. You can check the volume by pressing the volume up button on the side of your iPhone.
• Try playing audio from a different app. If the sound is only coming out of the ear speaker in one app, it is possible that there is a problem with the app.
• Try restarting your iPhone. Restarting your iPhone can fix a variety of minor software glitches.
• Check for updates. Make sure that your iPhone is running the latest version of iOS. You can check for updates by going to Settings > General > Software Update.

If you have tried all of the above and the sound is still only coming out of the ear speaker, then you may need to contact Apple Support for further assistance.