[CTcard]

I've seen it penalized before but it is a difficult and subjective call for officials.  There are lots of legitimate reasons for a defense to be barking out plays and adjustments pre snap so an official must gauge intent.

According to the rule, it doesn't matter if there are legitimate reasons for a defense to be barking.

Rule 7.1.5.5
"Defensive Team Requirements
...
No player shall use words or signals that disconcert opponents when they are preparing to put the ball in play. No player may call defensive signals that simulate the sound or cadence of (or otherwise interfere with) offensive starting signals."

Intent is not mentioned.

[CTcard]

I've seen it penalized before but it is a difficult and subjective call for officials.  There are lots of legitimate reasons for a defense to be barking out plays and adjustments pre snap so an official must gauge intent.

According to the rule, it doesn't matter if there are legitimate reasons for a defense to be barking.

Rule 7.1.5.5
"Defensive Team Requirements
...
No player shall use words or signals that disconcert opponents when they are preparing to put the ball in play. No player may call defensive signals that simulate the sound or cadence of (or otherwise interfere with) offensive starting signals."

Intent is not mentioned.