усилвам се означава в английски

intensify [intensified, intensifying, intensifies]▼(to become more intense)
verb
[UK: ɪn.ˈten.sɪ.faɪ] [US: ˌɪn.ˈten.sə.ˌfaɪ]

strengthen [strengthened, strengthening, strengthens]▼(to grow strong or stronger)
verb
[UK: ˈstreŋ.θn̩] [US: ˈstreŋ.θn̩]

swell [swelled, swollen, swelling, swells]▼(to grow gradually in force or loudness)
verb
[UK: swel] [US: ˈswel]