There are several possibilities here based on your description
#1 If your pet is making this sound and is also having a hard time catching her breath or seems to have trouble breathing, then this could potentially be a laryngeal paralysis (layrnx muscle not opening and closing properly). If this noise persists for more than 30 mins-1 hr then I would schedule an appt with your vet to get an exam done for further confirmation.
#2 However if your pet is coughing and not in distress, but it happens periodically throughout the day then this could be a kennel cough, which would require antibiotics from your vet
#3 Another possibility here is a reverse sneezing, although it more often sounds like a cough. Here is a video on reverse sneezing
https://www.youtube.com/watch?v=1UyBrb0HhpkIt is harmless and can be associated with allergies. If it continues for more than a couple of days, seek a vet for further exam of the oral cavity.