Who I have the same questioned this topic

Here is a solution that will come close to what you need. You need to turn on the microphone feature on your Samsung keyboard. To do so, open your Messages app and compose a message to open the Samsung keyboard. Locate the emoticon (smiley face) symbol to the left of the space bar.  Press and hold (long press) the smiley symbol. A list of options will appear above it.  Choose the microphone symbol.  Now you can press that symbol to compose text messages by speaking, as long as your Google Voice Typing setting is turned on (which mine was by default).  If Google Voice Typing is not turned on, go to the Language and Input settings under your Settings app to find it and turn it on. This is as close to SIRI text messaging as I can get without installing a third party app.