This script checks for some errors in translations, and helps the translators fix that.

appscript-v8.js

function onEdit (evt) {
 // permet de récuperer la valeur d'une cellule
  var range = evt.range;

  validateRow(range.getRow(), true);
}

function translationAutoFill(csv, tab_sep="\t", line_sep="\n"){
    var lines = csv.split(line_sep);
    var themes_inputs = document.querySelectorAll(".input-theme-text textarea");
    var sale_points_inputs = document.querySelectorAll(".input-sp-text textarea");
    if (themes_inputs.length != lines.length || sale_points_inputs.length != lines.length){
        throw new Error('Inputs fields and csv lines count are not equal.')
    }

    for(var i = 0; i < lines.length; i++){
        var line_parts = lines[i].split(tab_sep);
        themes_inputs[i].textContent = line_parts[0];
        sale_points_inputs[i].textContent = line_parts[1];
    }
}

function validateFullSheet(){
  var row = 1;
  var activesheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();

  while(String(activesheet.getRange('A' + row).getValue()).trim().length){
    validateRow(row);
    row++;
  }
}

function validateRow (row, logEditor = false) {
  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();
  var activesheet = spreadsheet.getActiveSheet();
  var activeUser = Session.getActiveUser();

  var themeCell = activesheet.getRange('F' + row);
  var sellingPointCell = activesheet.getRange('G' + row);
  var errorCell = activesheet.getRange('I' + row);
  var editorsCell = activesheet.getRange('K' + row);

  var spaceReg = /[\s\t]+/g;
  var theme = String(themeCell.getValue()).trim().replace(spaceReg, ' ');
  var sellingPoint = String(sellingPointCell.getValue()).trim().replace(spaceReg, ' ');
  var editors = String(editorsCell.getValue()).trim().replace(spaceReg, ' ').split('\n');

  var errors = [];
  var warnings = [];

  if (!theme.length && !sellingPoint.length){
    return;
  }

  // ===== THEME
  
  if (theme.length > 75){
    errors.push('- Le theme ne doit contenir plus de 75 caractères.');
  }

  if (theme.length < 30){
    errors.push('- Le theme doit contenir minimum 30 caractères. Décrivez bien le produit.');
  }

  if (theme.indexOf('-') >= 0 && !/ - /.test(theme)){
      errors.push('- Il semble que des espaces autour de - soient nécessaires.');
  }

  var _brandSpace = theme.indexOf(' - ');
  if ( _brandSpace >= 0 ){
    let chunk = theme.slice(_brandSpace, _brandSpace+4);

    if(chunk.toUpperCase() !== chunk){
      errors.push('- La lettre après la marque et - devrait être en majuscule.');
    }
  }

  // theme first char should be uppercase
  var tFistChar = theme[0];

  if ( tFistChar != tFistChar.toUpperCase()){
    theme[0] = tFistChar.toUpperCase();
  }

  // ===== SELLING POINTS

  if (sellingPoint.length > 150){
    errors.push('- Le selling point ne doit contenir plus de 150 caractères.');
  }

  if (sellingPoint.length < 30){
    errors.push('- Le selling point doit contenir minimum 30 caractères. Vendez bien le produit.');
  }

  // selling point first char should be lowercase
  var spFistChar = sellingPoint[0];

  if (spFistChar != spFistChar.toLowerCase()){
    sellingPoint[0] = spFistChar.toLowerCase();
  }

  if (/^(de|et|pour|avec) /i.test(sellingPoint)){
    warnings.push("- Eviter de mettre au début du selling point: pour, de, et, avec ....");
  }

  // ===== ALL

  // find duplicate
  var maps = {};
  var duplicates = [];
  var wordsToIgnore = {
    'de' : 1,
    'pour': 1,
    'avec': 1,
    'et': 1,
  };
  var cutReg = /[ ,;.:-]/;
  var words = theme.split(cutReg).concat(sellingPoint.split(cutReg));

  for(var i=0; i < words.length; i++){
    var w = words[i].toLowerCase();

    if (w.length > 1 && !wordsToIgnore[w]){
      if(maps[w]){
        if(maps[w] === 1){
          duplicates.push(w);
        }

        maps[w]++;
      } else {
        maps[w] = 1;
      }
    }

  }

  if (duplicates.length){
    warnings.push("- Des répétitions, utilisez des synonymes, ignorez ce avertisement s'il sagit de mots de liaisons: "+ duplicates.join(', '));
  }

  // ===== FINISH

  themeCell.setValue(theme);
  sellingPointCell.setValue(sellingPoint);

  if (errors.length){
    errorCell.setValue(errors.concat(warnings).join('\n\n')).setBackground('#FF0000').setFontColor("#FFFFFF");
  } else if (warnings.length){
    errorCell.setValue(warnings.join('\n\n')).setBackground('#F48024').setFontColor("#FFFFFF");
  } else {
    errorCell.setValue('ACCEPTABLE!').setBackground('#188038').setFontColor('#FFFFFF');
  }

  if(logEditor){
    var editorLogged = false;
    var user = activeUser.getEmail();// + ':' + Session.getTemporaryActiveUserKey();
    for(var i = 0; i< editors.length; i++){
      if (editors[i] === user){
        editorLogged = true;
        break;
      }
    }
    
    if (!editorLogged){
      editors.push(user);
    }
    
    editorsCell.setValue(editors.join('\n'));
  }
}