Hiccup was suddenly woken up by his mother, "Hiccup I have a really important question for
You" Valka stated, "what is it mom" he asked puzzled, "so I've been putting the pieces together about this for a while now, but are you able to understand all dragons"she said with a slight gleam in her eyes, "was it really that obvious" hiccup asked, "so it's a yes" she said happily as hiccup just nodded his head yes.
"Would you mind teaching me how to talk to the dragons properly" Valka stated getting more of a gleam in her eyes, "sure mom" he said 'not like it took me nearly 50 years to learn how….' He mumbled to himself loud enough for his mother to hear.
"What do you mean it took you nearly 50 years to learn you're only 20" Valka stated in confusion at her son, she knew he has always been somewhat too wise according to Stoick but this was different, "explain to me what you mean Hiccup please" she stated to him still shocked.
"Promise you won't tell a soul even my sister when she's back ok" hiccup asked and Valka nodded being open minded,after explaining she was shocked but mostly understood why he hid it, "so you're over 1000 years old but can change your looks to any age desired" she said being amazed, "yeah that's pretty much it about that part of my life" he stated not knowing what was about to happen, "now may I ask why you and toothless seem way closer then best friends hiccup" his mother asked waiting for the answer she knew would be said sooner or later, 'me and him are mates…' he mumbled still loud enough for his mother to hear, "hah Gobber owes me and Stoick a new axe each" she said with a smirk on her face, "wait you and dad knew about me and toothless being mates" he asked surprised, his mother just nodded while still smirking, " besides you and toothless being mates everything else is not going to get talked about with Gobber or Stoick ok, and nothing will be told to the villagers until you're ready hiccup" She said, "thank you mom, still abit shocked you knew about me and toothless though" he said and his mother laughed at that last bit, "what can I say I'm good at figuring things out most of the time" she said finishing the conversation so hiccup can go back to his nap.
Incase I forgot to mention Stoick did live in this since hiccup pushed him out of the way at the last possible second and they thought that hiccup living would attribute to the fact that toothless had just enough will to make the plasma blast unlikely to kill him.