Replace Accented Characters

See the code in action on Tinkercad

char accents[] = "àaâäcçeèé12ëïîioöoôûuUüùÂA34ÄÊ5EË6ÎÏ7ÔÖ8UÛÜ9ÀÇÉÈÊ0Ô";

void setup() {
  Serial.begin(115200);
  removeAccents(accents);
  Serial.println(accents);
}

void loop() {
}

void removeAccents(char Text[]) {
  int TextLength = strlen(Text);
  int i = 0;
  do {
    char c = Text[i];
    if ((uint8_t)c == 195) {
      char c2 = Text[i + 1];
      switch ((uint8_t)c2) {
        case 160 ... 166:
          Text[i] = 'a';
          break;
        case 167:
          Text[i] = 'c';
          break;
        case 168 ... 171:
          Text[i] = 'e';
          break;
        case 172 ... 175:
          Text[i] = 'i';
          break;
        case 177:
          Text[i] = 'n';
          break;
        case 178 ... 182:
          Text[i] = 'o';
          break;
        case 185 ... 188:
          Text[i] = 'u';
          break;
        case 189 ... 191:
          Text[i] = 'y';
          break;
        case 128 ... 134:
          Text[i] = 'A';
          break;
        case 135:
          Text[i] = 'C';
          break;
        case 136 ... 139:
          Text[i] = 'E';
          break;
        case 140 ... 143:
          Text[i] = 'I';
          break;
        case 146 ... 150:
          Text[i] = 'O';
          break;
        case 153 ... 156:
          Text[i] = 'U';
          break;
        default:
          break;
      }
      for (int j = i + 1; j < TextLength; j++) Text[j] = Text[j + 1];
      TextLength --;
    }
    i++;
  } while (i < TextLength);
}