If I've understood you correctly, you want to use the speakers (that you have been using with your old iPod Touch) with your iPhone 14.
However, an iPhone 14 does not have the 3.5mm headphone jack (the "large round socket") found on the 2nd generation iPod Touch.
Instead, the iPhone 14 relies on Bluetooth to connect to speakers and headphones, so the question is; does the speaker set have Bluetooth capability? If you don't know, either:
- check the instructions for the speakers if you still have them to see whether they mention a Bluetooth feature
- look for the Bluetooth symbol and/or button on the speakers (the button is used to connect to the iPhone, while the symbol indicates that Bluetooth is connected. The two functions may be in one button). The Bluetooth icon should look similar to one of the two shown below:

- let us know the make and model number of the speakers and perhaps we can find the information
If the speakers do not have a Bluetooth function, there are adaptors to convert the Bluetooth signal that have a 3.5mm socket into which you could plug your round plug, but they may be difficult to find and expensive to buy. It might be easier to buy a Bluetooth speaker instead.