Short answers, pulled from the story.
Bragi is the god of poetry in Norse mythology, described by Snorri Sturluson in the Prose Edda as renowned for wisdom, eloquence, and command of language. He is the husband of Iðunn and appears in Valhalla welcoming fallen kings in the skaldic poems Eiríksmál and Hákonarmál.
Most scholars interpret Bragi as a posthumous mythologization of Bragi Boddason, a 9th-century Norwegian court poet who served Swedish kings including Ragnar Lodbrok and is traditionally regarded as the first skald. Scholars such as Margaret Clunies Ross and Heinz Klingenberg suggest his elevation to divine status occurred in the late 10th century.
The Ragnarsdrápa is a poem attributed to Bragi Boddason, composed in honor of Ragnar Lodbrok and describing scenes painted on a decorated shield that Ragnar gave to Bragi. The images included Thor fishing for Jörmungandr, Gefjun ploughing Zealand from the soil of Sweden, and the battle of Hamdir and Sorli against King Jörmunrekk.
In Lokasenna, composed around 1200 AD, Bragi is the first of the gods at Ægir's feast to address Loki after Loki forces his way in, offering him a horse, a sword, and a ring to leave peacefully. Loki mocks him as the most cowardly of the gods, calling him 'Bragi the bench-ornament', and the confrontation ends when Iðunn intervenes to urge restraint.
The Old Norse noun bragr has two meanings that both connect to the name: 'poetry' and 'the first, the noblest'. A comparison with Old English brego meaning 'lord or prince' has also been proposed but remains uncertain. Scholars have not resolved which sense underlies the divine name.
In Sigrdrífumál, runes are described as being carved on a wide range of objects including Sleipnir's teeth, a bear's paw, an eagle's beak, a wolf's claw, and Bragi's tongue. Those runes are then shaved off, mixed with mead, and distributed to the Æsir, elves, Vanir, and humans as speech runes, birth runes, ale runes, and magic runes.