Portuguese has a strange coincidence in the preterit perfect tense of the verbs ir (to go) and ser (to be): they are conjugated exactly equally.
Portuguese — English to go | English to be
- Eu fui — I went | was
- Tu foste — You (singular) went | were
Ele/Ela foi — He/She went | was
Nós fomos — We went | were
- Vós fostes — You (formal / plural (outdated)) went | were
- Eles/Elas foram — They (masculine/feminine) went | were
What is the name of this verb conjugation convergence phenomenon? Do you know more examples of it occurring in any language?