The Myth: Your voice, the way you talk is not adequate to the task of good fiction. You’ll need to find a literary “voice” and then tell stories in that voice.

Here’s an exercise*.
Sit down and write for 30 minutes. Try to write a great first page of fiction – the start to a great novel or short story.

Now, go to the library and find the fiction stacks (I am sure you already know where they are). Start pulling down modern^ novels and short story collections. Read the first lines, maybe the first pages of them. Read the first pages of 30 or 40 novels and/or short stories, more if you have the time. Here is what you’ll find. You will find simple and direct language, clear and concise images. You may not understand exactly where the story is going, but what you’ve read will be clear and straight forward, not open to interpretation. Here are a couple of examples:
“Officially, I started destroying my life that Wednesday morning. But it had been on my mind for a while.” [from The Next Right Thing by Dan Barden]
“The two old men slept on the bank of the dirty flooded river, and from above they would’ve appeared as dead men – corpses washed ashore and left to rot in the coming sun.”

[from What This River Keeps by Greg Schwipps]

Look back at what you wrote. What you wrote is likely not simple and direct. It is complex and trying to do too much. It is working to impress the reader with the author’s skill.
Rewrite your opening as if you were telling your best friend.
There, that is your voice. Write in that voice. Keep writing in that voice.

The Truth: Your voice – the way you talk – is fully adequate to the task of good fiction. Write in your voice. Tell stories in that voice.

*The impact of this exercise will vary depending on how much fiction you’ve written. The only way to become a good writer is to write – everyday, for years and years.
^Published since 1980.