"yíní-" meaning in Navajo

{
  "etymology_templates": [
    {
      "args": {
        "1": "nv",
        "2": "yi-",
        "3": "ni-"
      },
      "expansion": "yi- + ni-",
      "name": "af"
    }
  ],
  "etymology_text": "From yi- + ni-.",
  "head_templates": [
    {
      "args": {
        "1": "nv",
        "2": "prefix"
      },
      "expansion": "yíní-",
      "name": "head"
    }
  ],
  "lang": "Navajo",
  "lang_code": "nv",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Navajo entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Navajo terms prefixed with ni-",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Navajo terms prefixed with yi-",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages using catfix",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Marks a second person singular subject of a yi-perfective verb"
      ],
      "id": "en-yíní--nv-prefix-VnkpCa7t",
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "yíní-"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "nv",
        "2": "yi-",
        "3": "ni-"
      },
      "expansion": "yi- + ni-",
      "name": "af"
    }
  ],
  "etymology_text": "From yi- + ni-.",
  "head_templates": [
    {
      "args": {
        "1": "nv",
        "2": "prefix"
      },
      "expansion": "yíní-",
      "name": "head"
    }
  ],
  "lang": "Navajo",
  "lang_code": "nv",
  "pos": "prefix",
  "senses": [
    {
      "categories": [
        "Navajo entries with incorrect language header",
        "Navajo lemmas",
        "Navajo prefixes",
        "Navajo terms prefixed with ni-",
        "Navajo terms prefixed with yi-",
        "Pages using catfix",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "glosses": [
        "Marks a second person singular subject of a yi-perfective verb"
      ],
      "tags": [
        "morpheme"
      ]
    }
  ],
  "word": "yíní-"
}