var digits = new[] { 1, 2, 3 };
var german = new[] { "ein", "zwei", "drei" };

var q = digits.Select( ( digit, index ) => new { Value = digit, Index = index } )
              .Join( german.Select( ( phrase, index ) => new { Value = phrase, Index = index } ),
                     _ => _.Index, _ => _.Index, // Вот это очень плохо читается; с первого взгляда не очевидно, что именно тут индексы на равенство и сравниваются.
                     ( digit, phrase ) => new { Digit = digit.Value, Phrase = phrase.Value }
                    );
foreach ( var translation in q )
  Console.WriteLine( "'{0}' stands for {1}", translation.Phrase, translation.Digit );

static class Extensions
{
    public static IEnumerable<TResult> Zip<TFirst, TSecond, TResult>(
        this IEnumerable<TFirst> first,
        IEnumerable<TSecond> second,
        Func<TFirst, TSecond, TResult> func)
    {
        if (first == null)
            throw new ArgumentNullException("first");

        if (second == null)
            throw new ArgumentNullException("second");

        if (func == null)
            throw new ArgumentNullException("func");

        using (var e1 = first.GetEnumerator())
        using (var e2 = second.GetEnumerator())
            while (e1.MoveNext() && e2.MoveNext())
                yield return func(e1.Current, e2.Current);
    }
}

class Program
{
    static void Main()
    {
        var digits = new[] { 1, 2, 3 };
        var german = new[] { "ein", "zwei", "drei" };
        var q = digits.Zip(german, (digit, phrase) => new {Digit = digit, Phrase = phrase});
        foreach (var translation in q)
            Console.WriteLine("'{0}' stands for {1}", translation.Phrase, translation.Digit);
    }
}

If one input list is short, excess elements of the longer list are discarded.

D>    public static IEnumerable<TResult> Zip<TFirst, TSecond, TResult>(
D>        this IEnumerable<TFirst> first,
D>        IEnumerable<TSecond> second,
D>        Func<TFirst, TSecond, TResult> func)
D>

    public static IEnumerable<KeyValuePair<TFirst, TSecond>> Zip<TFirst, TSecond>(
        this IEnumerable<TFirst> first,
        IEnumerable<TSecond> second)

fib :: Integer -> Integer
fib n = fibs !! n
  where
    fibs = 0 : 1 : zipWith (+) fibs (tail fibs)

var q = new[] { 1, 2, 3, 4 }.ZipWith(i1, i2 => i1 + i2, new[] { 1, 2, 3 }).Take(2);

      int[] digits ={ 1, 2, 3 };
      string[] german = { "ein", "zwei", "drei" };

      // вариант 1
      var c = digits.Select((digit, index) => new { Digit = digit, Phrase  = german[index] });

      // вариант 2, медленный
      var d = digits.Select((digit, index) => new { Digit = digit, Phrase = german.Skip(index).First() });

      foreach (var e in c)
      {
          Console.WriteLine("" + e.Digit + "  " + e.Phrase);
      }

    static void Main(string[] args)
    {
        var c = from a in digits(10).Select((e, i) => new { e, i })
                join b in german(10).Select((e, i) => new { e, i })
                on a.i equals b.i
                select new { d = a.e, f = b.e };
        foreach (var e in c)
        {
            Console.WriteLine("" + e.d + "  " + e.f);
        }
    }

    static IEnumerable<int> digits(int n)
    {
        for (int i = 1; i <= n; i++)
            yield return i;
    }

    static IEnumerable<string> german(int n)
    {
        for (int i = 1; i <= n; i++)
            yield return string.Format("{0:D2}", i);
    }

    var digits = new[] { 1, 2, 3 };
    var german = new[]  { "ein", "zwei", "drei" };
    var q = Enumerable.Range(0, digits.Count()).Select(i => new { Digit = digits[i], Phrase = german[i] });

ЮБ>    var digits = new[] { 1, 2, 3 };
ЮБ>    var german = new[]  { "ein", "zwei", "drei" };
ЮБ>    var q = Enumerable.Range(0, digits.Count()).Select(i => new { Digit = digits[i], Phrase = german[i] });
ЮБ>

var digits = new[] { 1, 2, 3 }.AsEnumerable();
var german = new[] { "ein", "zwei", "drei" }.AsEnumerable();

S>var digits = new[] { 1, 2, 3 }.AsEnumerable();
S>var german = new[] { "ein", "zwei", "drei" }.AsEnumerable();
S>

    var digits = new[] { 1, 2, 3 }.AsEnumerable();
    var german = new[]  { "ein", "zwei", "drei" }.AsEnumerable();
    var z = Enumerable.Range(0, digits.Count()).Select(i => new { Digit = digits.ElementAt(i), Phrase = german.ElementAt(i) });