Lächeln is grammatically peculiar because it does not have a generally accepted plural form, although the word is clearly countable. One can say: ein Lächeln − “a smile”; or: sein erstes und sein zweites Lächeln – “his first and his second smile”. But actual plural usage occurs only seldom, chiefly in the vernacular: seine beiden Lächeln – “his two smiles”. This usage is awkward and may sound ungrammatical to many language users.
Generally the plural needs to be paraphrased (for example: die beiden Male, wo er gelächelt hat – “the two times that he smiled”). Apart from this, German often uses the singular where English would use the plural: das Lächeln der Leute – “the smiles of the people”.