Poppy is one of more than 45,000 children in the UK for whom being deaf is a part of everyday life.
The 14-year-old, who is profoundly deaf, says the yellow Labrador has increased her confidence and helps her sleep at night.
She is one of 27 children in the UK to have been given a hearing dog by the charity Hearing Dogs for Deaf People.
It was not until Poppy was nine years old that civil engineer Richard and housewife Rebecca noticed small changes in their daughter's behaviour which concerned them.
"She was turning the volume up on the TV," said Rebecca. "When she was in the car she wouldn't hear me when I was talking to her, even though her brothers and sister could hear in the back."
Concerned, they had Poppy, from Cwmbran, Torfaen, referred to an audiologist who was shocked to discover the schoolgirl was profoundly deaf and could barely hear a thing, but had been covering this up by lip-reading.
Despite her acute deafness there was no affect on her schoolwork so the early signs had not been noticed.
Rebecca said: "What we realised when she was diagnosed was that she had become quite proficient in lip reading, which was how she had managed to wing her way through school. No-one had noticed as there was no change in her schoolwork."
She was diagnosed with the rare disease Autoimmune Polyendocrine Syndrome type 1.
Although she was given hearing aids to wear in each ear, she became withdrawn and lacked confidence both socialising and doing little things like going to the shops.
She had trouble getting to sleep at night as she could not wear hearing aids, which meant should could not hear anything at all and was constantly on edge about someone coming into her room.
Poppy struggled by for three years feeling more and more isolated until her mother found out about hearing dogs, who help deaf people in a similar way to guide dogs. There are 850 deaf people, mostly adults, partnered with dogs in the UK.
Because of her profound deafness, Poppy was the first child to be partnered with a hearing dog in Wales. The dog was named Tanni after Baroness Tanni Grey Thompson and one of just 12 given out that year.
Source: Hearing Dogs for Deaf People
A year on and Poppy says Tanni has changed her life.
"Having her has built my confidence," said Poppy. "She gives me more independence. Before when my mum went out I would be left at home, now I can go with her and go into shops. Before I was very reluctant to go into a shop and pay by myself. I was worried as they wouldn't know I was deaf, but now they can see from Tanni that they need to speak clearly as she wears a special harness when we're out.
"Another good thing is that people ask questions about Tanni and I feel happy talking about her. It has made me more confident answering questions in general.
"I have got a best friend."
Tanni goes everywhere with Poppy, apart from school. She has been trained to let Poppy know if there is a fire alarm or if her mother wants her.
Poppy said: "She wakes me up in the morning, if my mum wants to let me know we are going out or it is tea time she will write a note and put it in a purse which Tanni then brings in her mouth to me. So she will come up to get me and then nudges me.
"As I get older and more independent we could train her to do the doorbell, phone and text messages."
And Poppy has finally had the good night's sleep she had hoped for.
She said: "I used to sleep with the door open as I didn't know who was coming in to the room, I had the bed so I could see straight down the landing with the door open.
"Now Tanni wakes me up if someone comes in, so I can sleep with the door shut."
Andrew James, National Client Services Manager for Hearing Dogs for Deaf People, said: "We have now placed 27 hearing dogs with deaf children across the UK, and we are so pleased that Poppy and Tanni are the first child partnership in Wales.
"The Hearing Dogs for Deaf Children project has been a huge success since it was launched in 2012 and we have seen increasing interest each year, so the charity plans to expand our work with children over the coming years.
"Hearing dogs have an important influence on a deaf child's life, and we couldn't be happier with the positive difference that Tanni has made to Poppy and her family."
There are currently 29 deaf people with hearing dogs in Wales.
A schoolgirl has become the first child in Wales to be given an official hearing dog.