Honey Salt and Bitter Sugar

Sougo Kawano is a high school student with a severe communication disorder who doesn't have any friends. As such, he spends his days in school avoiding everybody. Sougo's only joy in life is to pet the flowers growing behind the gymnasium. But one day, even though no one else usually comes by there, Tani, a senior, shows up. Sougo gradually finds himself falling for Tani, who's kind and mysteriously attractive. However, Sougo then finds out about Tani's friend, Shun, whom Tani considers "important" to him...

(Source: Renta!)