vi_no_phonology.cs

 //https://www.jetbrains.com/help/resharper/Spell_Checking.html#configuring-respeller-inspections
 void ex()
        {
            string path = @"D:\API\dictionaries\dictionaries\vi\index.dic";
            string newpath = @"D:\API\dictionaries\dictionaries\vi\index2.dic";
            string text = File.ReadAllText(path);
            string newtext = RemoveSign4VietnameseString(text);
            string[] lines = newtext.Split(
                new[] { "\r\n", "\r", "\n" },
                StringSplitOptions.None
            );
            
            List<string> ss = lines.ToList().Distinct().ToList();
            ss.Sort();
            string[] strings = ss.ToArray();
            strings[0] = strings.Length.ToString();
            string textfilter = string.Empty;
            foreach (string s in strings)
            {
                textfilter += s+"\n";
            }
            File.WriteAllText(newpath,textfilter);
        }
public static string[] RemoveDuplicates(string[] s)
        {
            HashSet<string> set = new HashSet<string>(s);
            string[] result = new string[set.Count];
            set.CopyTo(result);
            return result;
        }
        public static string RemoveSign4VietnameseString(string str)
        {
            for (int i = 1; i < VietnameseSigns.Length; i++)
            {
                for (int j = 0; j < VietnameseSigns[i].Length; j++)
                    str = str.Replace(VietnameseSigns[i][j], VietnameseSigns[0][i - 1]);
            }
            return str;
        }


private static readonly string[] VietnameseSigns = new string[]
        {

            "aAeEoOuUiIdDyY",

            "áàạảãâấầậẩẫăắằặẳẵ",

            "ÁÀẠẢÃÂẤẦẬẨẪĂẮẰẶẲẴ",

            "éèẹẻẽêếềệểễ",

            "ÉÈẸẺẼÊẾỀỆỂỄ",

            "óòọỏõôốồộổỗơớờợởỡ",

            "ÓÒỌỎÕÔỐỒỘỔỖƠỚỜỢỞỠ",

            "úùụủũưứừựửữ",

            "ÚÙỤỦŨƯỨỪỰỬỮ",

            "íìịỉĩ",

            "ÍÌỊỈĨ",

            "đ",

            "Đ",

            "ýỳỵỷỹ",

            "ÝỲỴỶỸ"
        }; 

OutPut:
https://github.com/chuongmep/dictionaries/blob/main/dictionaries/vi/index_no_phonology.dic