Hi,
No need to create a separate text field!
If you don't need to change the speaker name's color, you can inspect the subtitle panel's StandardUISubtitlePanel component.
Tick Add Speaker Name, and set Add Speaker Name Format to something like:
<font="Gothic"><size=30>{0}</size></font>: {1}
The <tags> above assume you're using TextMesh Pro. (See
TextMesh Pro Support.) If you're using legacy Unity UI Text, you can use
rich text codes.
The {0} will be replaced by the speaker's name, and {1} will be replaced by the subtitle text.
If you do need to change the speaker name's color, too, then UNtick Add Speaker Name. Instead, add a Dialogue Actor component to the speaker's GameObject. Set the Actor dropdown. Then tick Dialogue UI Settings > Set Subtitle Color and Apply Color To Prepended Name. Set the Prepend Actor Name Format, for example to something like:
Prepend Actor Name Separator: -
Prepend Actor Name Format: <font="Gothic"><size=30>{0}</size></font>{1}